Perhaps it was my daughters singing along with Hannah Montana—“Get up, get loud, we’re pumping up the party now!”—eight times in a row that morning. Or maybe it was the 16 times I overheard High School Musical and High School Musical 2 playing on the television in the living room, or the several hundred dollars my wife and I spend on Disney tween products—aimed at nine- to 14-year-old girls—every year. Or the fact that a magazine (thankfully, not this one) asked me to profile a Disney tween star and then, almost before I could ask “Who?,” told me that another publication had beaten them to it. Finally, after my eight-year-old daughter pointed to a picture of Hillary Clinton and said she was supporting her for president “because she’s named Hillary, like Hilary Duff,” I decided I had to know: Who is doing this to me?

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The original Disney formula, perfected through multiple generations of anthropomorphic animated animals, was simple: Develop adorable children’s properties—Mickey Mouse, the Lion King—and then franchise the characters to within an inch of their cuddly lives, across many platforms around the globe for vast amounts of dollars, euros, yen, and yuan. Disney gets credit for conceiving of and executing synergy long before other media conglomerates made it a bad word. Yet Disney executives were spoiled by their early success. They became too reliant on aging animated characters and couldn’t replicate the magic in the live-action world. The result was a gaping—and costly—hole in Disney’s demographic: While the company excelled at grabbing children under eight by their tiny lapels with Mickey Mouse and his ageless friends, it was losing more and more of that audience as it grew up and migrated elsewhere. The fear, on Wall Street as well as at Disney headquarters in Burbank, California, was that if the kids left, they would never come back. (View a slideshow of the young stars and executives driving Disney to new heights.)

And indeed, that was proving true. Disney’s vaunted animation businesses were failing with tweens, and its young-adult franchises like Pirates of the Caribbean were slicing over the pony­tailed heads of that huge audience. Not anymore. As the peppy lyrics coming from my daughters’ bedroom can attest, the synergy is back, and it’s smacking the sweet spot that Disney had been missing. That squeak you hear is Mickey getting squashed under the wheels of the Disney Channel marketing machine as it pushes Hannah Montana, the Jonas Brothers, High School Musical, and a host of other tween products into our living rooms, if not down our throats.

Credit for this astounding turnaround goes to Anne Sweeney, president of Disney-ABC Television Group since 2004, who joined the company after a stint as chairwoman and C.E.O. of FX Networks. “We found there was this huge demo that was too old for Nickelodeon and too young for MTV. We realized this was an opportunity for Disney to establish itself in the lives of these kids.”

Sweeney has done more than that. She has made the Disney Channel the major profit driver in the company. Ten years ago, it was a stagnating pay-TV service that programmed for the kindergarten crowd in the morning and adults at night. Nickelodeon was closing in. But in 2007, Disney’s cable networks, including ESPN and the Disney Channel (a tween powerhouse), were the fastest-growing division in the House of Mouse, boosting the company’s ­media-division revenue 12 percent over the previous year, to more than $9 billion, and increasing income during the same period by an astonishing 19 percent, to $3.6 billion. (And those numbers don’t include the huge ancillary revenues that the franchises generate in the $2.3 billion consumer-products division.) The Disney Channel has been adding a million viewers a month—every month—for the past five years.

The Disney Channel is probably the greatest teen-star incubator since the N.B.A. stopped drafting high schoolers. It has been No. 1 in prime-time cable ratings among viewers under 18 for the past seven years, and in 2007, it held the top spot among total viewers. Walt Disney Records, which releases the soundtracks for the Disney Channel’s shows, and Hollywood Rec­ords, another Disney subsidiary, have become Motowns for minors, and last year, though CD sales were down 20 percent across the music industry, the Disney labels posted a high-single-digit gain over 2006’s figures. And that success—High School Musical was the bestselling CD of 2006; High School Musical 2 and Hannah Montana 2 were both in the top six of 2007—was achieved without any substantial Top 40 radio exposure. Of course, Disney doesn’t really need to go outside the corporation for airplay because Radio Disney is the most popular radio network for tweens, reaching 97 percent of the country’s markets.

Using a multiplatform attack—television, radio, internet, music, consumer products, theme parks—Disney has succeeded where so many, including Sony, Time Warner, and Viacom, have failed. Executives at the Disney Channel call 10-year-olds their “sweet spot,” and it will be virtually impossible for a competing faith—O fallen idols of Nickelodeon, take heed!—to win back the hearts, minds, and allowances of America’s tween true believers. “Some of Disney’s other assets—the parks and resorts, the filmed entertainment—have slowed down on the revenue side,” says Joe Bonner of Argus Research. Revenue at the movie studio was down 1 percent in 2007 from 2006, and revenue from the theme parks was up just 7 percent, a decrease from the 10 percent gain the year before. But, Bonner says, Disney’s tween business is “creating explosive value.”

It’s also helping Disney get back to what it does best—cross-selling in a way that had been impossible given the recent dry run for the company’s new characters. The suits over at Disney have no compunction about using words like brand, franchise, and property to describe Hannah Montana, Raven-Symoné, or High School Musical—another sign of the central role tween products now play at the company. Their importance is apparent from Disney’s most recent annual report, on whose cover Musical has displaced Mickey Mouse, Johnny Depp, and various Pixar characters.

During the first week of February, the company held an 80-person, all-platform international meeting to discuss Hannah Montana’s future. Publishing, theme parks, radio, games, internet, consumer products, theater, feature films—every Disney business was represented at this Montanastock to take its slice of Miley Cyrus, the 15-year-old daughter of country singer Billy Ray Cyrus, who plays Hannah Montana.

Anne Sweeney, 50, is a fit, trim woman with short hair and a thick diamond in each ear. She is sharp-featured and pretty in a low-key way that doesn’t interfere with her being taken seriously. Her broad American accent betrays no provenance. (She grew up in Kingston, New York, about halfway between New York City and Albany.) On a rainy, late- winter day, she is back in New York to accept a Golden Mike Award from the Broadcasters Foundation of America and attend a Disney board meeting later that afternoon. Over breakfast, she fiddles with her earrings, sips her coffee, and smiles frequently; she has good reason to be happy. After years of regularly making every roster of powerful women in business, Sweeney can now claim the top spot on a much more exclusive list: those who might succeed Disney C.E.O. Bob Iger.

Sweeney, who has a 17-year-old daughter and 22-year-old son, has spent her entire career in television, working at Nickelodeon before going to FX. She recalls being at Nickelodeon in the early ’90s, launching its international channels and trying to beef up its Nick at Nite lineup, looking across the marketplace at Disney and thinking, “Man, the things I could do if I worked there...” She was particularly intrigued by the opportunity to promote and market through different channels, something that just wasn’t in the water at Viacom. “Synergy is so rooted in the Disney culture, it is unassailable,” she says. “It is the through line to everything we do. It’s not like anywhere else.”

Sweeney’s tween takeover began with her decision to make the Disney Channel part of the basic cable package in 1997. Seeking to connect with the bill payers (adults) rather than with kids, the channel had been programming costume dramas that weren’t exactly tween fodder—like Ike and Mamie: The Eisenhower Years. “We began trying everything,” Sweeney says of her reboot. “We wanted tweens, but there was no formula out there for how to get them. We tried animal shows, game shows. We put Mad Libs on the air.”

Nothing stuck until Sweeney began airing Disney Channel Concerts, televised pop-music showcases at Disney theme parks that helped propel the careers of Christina Aguilera, the Backstreet Boys, ’N Sync, LeAnn Rimes, and Britney Spears, among others. Sweeney and Rich Ross, the president of Disney Channels Worldwide, soon realized that after launching those acts, Disney wasn’t in a position to profit from the many millions in CD and product sales it helped generate. At the same time, Disney found itself at risk as those acts began to alienate fans—hello, Britney!—and, even more worrying, parents. Sweeney and Ross came up with the idea of creating their own acts. “We’re not naive or coy about saying that we knew if we could do it for others, we could do it for ourselves,” Ross says.

The prototype was, in many ways, Hilary Duff, star of the sitcom Lizzie McGuire, about a self-conscious middle schooler dealing with predictable teen issues. The show, created by Terri Minsky, was the Disney Channel’s first big hit and became the testing ground for Disney’s multiplatform approach to colonizing my life. Television soundtracks had historically never been big sellers; before Lizzie McGuire, networks didn’t even bother to release them for most of their shows. But Disney Music began selling millions of Lizzie McGuire soundtracks, setting the stage for Hilary Duff, pop star. “Lizzie McGuire was our first success,” says Disney Channel’s president for entertainment, Gary Marsh, who Sweeney insists shares credit for the channel’s success, along with Ross and other executives. “But Hannah Montana makes Lizzie look like a drop of water.”

Indeed, you haven’t seen pure excitement if you haven’t been at an elementary-school dance when the D.J. drops Hannah Montana’s “The Best of Both Worlds.” Montana’s hits are infectiously simple—sugary, big-hook R&B songs with heavily processed vocals and rousing “you go, girl!” choruses—and they drive tween girls to demand ever more iterations of basically the same product. In my house, there are at least six Hannah Montana CDs, including Hannah Montana 2: Non-Stop Dance Party; Hannah Montana: Karaoke From the Hit TV Show; Hannah Montana 2: Meet Miley Cyrus; and Hannah Montana 2: Rockstar Edition, each of which, as far as I can tell, contains the same songs remixed to annoy me in a slightly different way.

And here’s the added genius: Since I don’t want my kids to troll peer-to-peer sites for free music—who knows what else is out there—I dutifully order the stuff from Amazon or plunk down my plastic at one of the few remaining CD stores. At Wal-Mart, Disney benefits from being one of the few brands that retailing’s biggest bully doesn’t dare push around. What Disney seems to have figured out is that tweens may be the last group of consumers who will buy music—or throw a fit until it is purchased for them. In other words, at a time when most consumers expect music to be either free or dirt cheap, Disney now owns one of the last corners of the planet where people actually pay for CDs. “Parents will buy two or three Disney CDs to give one to each of their kids,” says Abbey Konowitch, vice president of Disney’s Hollywood Records, “whereas at a college dorm, one person might buy a CD, and 10 people will copy it.”

Of course, Disney has already rolled out the Hannah Montana franchise across its various divisions. Her national tour was sold out, and tickets to the 3-D movie of her tour were almost impossible to get. The film was No. 1 at the box office on its opening weekend and went on to gross $70 million; another feature film is in the works. Her likeness appears on everything from cereal boxes to musical instruments to digital cameras, and she is moving more product than a Chinese container port.

On a recent afternoon while waiting to see Gary Marsh, I found myself in an atrium with a few dozen young actresses there to audition for a Disney Channel Original Movie—DCOM in the company lingo. Most of the girls—impossibly cute, perfectly featured, tirelessly smiling—sat with their mothers, poring over the page of dialogue they were to read during the casting session. A few stood up in order to get more into character, gesticulating toward Cheetah Girls posters as they ran their lines. The stench of collective aspiration in the room was as thick as the smell of peach and strawberry body spray. They all want it so badly, and only a very few can get it. Disney Channel execs are famously finicky about their casting, insisting, for example, that they meet and meticulously appraise the parents of any child they are considering hiring. Today’s callback is for a project starring Demi Lovato and Selena Gomez, tentatively titled Princess Protection Program, about a princess who has to enter the witness protection program. It will be the 76th DCOM and, these nervous young thespians hope, a star-launching vehicle as powerful as the 61st DCOM: High School Musical.

Produced for $4.2 million in 2005, High School Musical has spawned a franchise that is worth, according to some analysts, half a billion dollars. The burst-into-song story of a high-school basketball player who secretly wants to sing in the school play, Musical is the most successful made-for-TV movie, the most successful cable movie, and the most successful television-musical franchise in history. More than 8 million CDs, 8 million DVDs, and 9 million novels have been sold, and it has toured as a sold-out concert and ice show. Nearly 3,000 high schools in the U.S. have staged productions of the show, and local-language versions are being produced in Argentina, Brazil, India, and Mexico. High School Musical 2 has put up similar numbers and sold 3.8 million videogames. High School Musical 3 will begin filming on April 22; prescient Disney execs got it locked down before the writers strike, and it will be ready for release in October. Disney Consumer Products has estimated that retail sales generated by the franchise in 2008 will be more than a billion dollars.

High School Musical has the potential to be Hannah times 10, as the same multi­platform success that has worked for one star could be replicated throughout the huge cast of Musical. And Disney execs are paying close attention. Director Kenny Ortega recalls that before the first High School Musical, there would be one or two corporate types sitting in on develop­ment meetings. For High School Musical 3, development meetings require entire conference rooms, as a dozen suits drop in to hear about Ortega and writer Peter Barsocchini’s vision for expanding the franchise. “Very carefully” is Ortega’s short version of how he will proceed. “This is the last High School Musical as we know it, with these characters. But this is a place, a concept, that will keep on giving.” The new film’s budget exceeds $30 million, and star Zac Efron will reportedly pocket $5 million, more than the entire budget for the first Musical (though Disney says that number is too high). But Ortega is eager to assure me, and perhaps his Disney bosses as well, that he will be introducing new characters, further extending the brand.

Ortega, a onetime member of subversive rock act the Tubes—“I was definitely the most conservative member,” he quickly points out—believes that the simplicity as much as the casting of Musical has made it so enduring. The story is Romeo and Juliet, without the Montagues, Capulets, or Friar Laurence. Or any romance. Or danger. Or tension greater than “Will he make it to rehearsal on time?” The two main characters don’t even kiss—but they do exchange a longing glance.

And kids love it. The secret to the success of this franchise, like so many of Disney’s other tween machines, is that it aims even younger than other pop culture.

The success of the first High School Musical, which aired in January 2006 and has been seen by an estimated 250 million viewers, and High School Musical 2, which essentially duplicated its predecessor’s results, prompted Disney to plan to release High School Musical 3 in theaters. Executives were most likely seduced by the simple multiplication of 18.6 million (the audience for High School Musical 2 when it made its debut in August 2007) by $12 (the price of a movie ticket). No less an authority on starmaking than Simon Cowell has called the Musical franchise the only thing out there that threatens his American Idol for supremacy in the music biz.

Of course, as Disney execs are quick to remind, this is not a science, and as successful as they have been, they insist that a certain magic has to happen. “You can never predict who will be the next Miley Cyrus,” Hollywood Records’ Konowitch says. But Disney’s tween star factory has come as close to finding the formula as any entertainment conglomerate ever has. Disney is unceasingly careful, excising songs that are too edgy from soundtracks and combing through TV scripts to make sure that material meant to work on two levels, á la The Simpsons, doesn’t alienate kids. “The story can’t hinge on any reference our audience doesn’t easily get,” Marsh explains. “We don’t want any obstacle there.”

Making the magic happen is not easy, Marsh insists, but plenty of other companies are trying: Universal, with its Slumber Party Girls on CBS, and Nickelodeon, with Naked Brothers Band and Zoey 101. But Disney’s competitors are far enough behind that it will take a colossal screwup for the company to lose its grip on this demographic. At Disney, it’s all about the platforms. Universal had to go to CBS to get its act on television, hence surrendering that portion of creative control and potential profit. It is almost embarrassing to say, so discredited has the term become in American business, but Disney’s tween success may well be the foremost example of the proper execution of synergy. A competitor—or a beleaguered parent—might well ask in despair, What can possibly derail the tween assembly line?

At one point, while I’m sitting in Marsh’s corner office, I mention Musical star Vanessa Hudgens and the nude photos of her that turned up on the internet last year. I can hear a 767 jet bank into its approach to nearby Burbank airport as Marsh and Disney Television senior vice president of kids communications Patti McTeague exchange quick, concerned glances. After Nickelodeon’s Jamie Lynn Spears, Britney’s 16-year-old sister, announced in December that she was pregnant—forcing the network’s executives to figure out how to work that twist into a tween plot—it became clear that the greatest threat to the mighty tween franchises of our time is the kids themselves. “It keeps me up at night,” Marsh admits, after a few seconds of silence. “Our job is to make sure none of this stuff gets out of control.”

These two incidents, and the ongoing scandals around other former Disney kids—Britney, Lindsay Lohan—make it obvious just how vulnerable these monster franchises can be, built as they are upon the mouths of babes. “For Miley Cyrus to be a ‘good girl’ is now a business decision for her,” Marsh says. “Parents have invested in her a godliness. If she violates that trust, she won’t get it back.”

Of course, something will definitely happen to her: She will grow up. And Disney has plenty of contingencies in place for that catastrophe. In the middle of Hannah Montana’s smash concert film, the Jonas Brothers, Disney’s hottest new tween act, take the stage for three songs. The trio, who look like miniaturized asexual Mick Jaggers, perform songs from their upcoming CD. They will also star in a Disney feature film, Camp Rock, as well as a Disney television series and their own reality show. Disney execs had been eyeing the Jonas Brothers for a few years but stayed away because the brothers were under contract with Sony. As soon as Sony dropped them, Disney pounced and immediately developed the requisite franchise-making live-action TV show for the boys.

As for the Jonas Brothers’ prospects, my eight-year-old declared that their mini-set was her favorite part of the Hannah Montana concert movie. Disney’s future looks bright.

Later, as I was driving from the Disney Channel offices to the Disney studio lot to meet with Hollywood Records execu­tives, past karate dojos and car-wash emporiums along one of Burbank’s low-slung boulevards, I was listening to Steve Jones, the Sex Pistols guitarist who now hosts Jonesy’s Jukebox, a popular radio show. He was interviewing Mike Chapman, producer of such acts as Blondie and the Knack, which were, in a sense, the teen-pop music of their day, because there wasn’t a distinct tween market in the late ’70s.

Chapman was lamenting the end of the music business that he had known, which was done in not just by obvious problems like file sharing and declining revenues but also by the plethora of records with plastic-sounding, heavily processed vocals—the music “sold in Kmart,” as Jones called it. In other words, the Hannah Montanas and Hilary Duffs. Jones pointed out that the whole process of manufacturing pop idols was artificial—“soulless, not very rock ’n’ roll.”

No, it’s not very rock ’n’ roll. But that’s not really the point, is it?