If the clothes make the man, what does that make the man who makes the clothes?

To hear tailors tell it, they don’t just make high-profile people look good; they stitch together the confidence executives and entertainers need to perform under pressure. They can bestow credibility with judicious use of pinstripes, or panache with a strategically placed trouser dart. They’re the people who can make beanpoles look buff and “jolly” guys look svelte, all without doing a crunch or lifting a free weight.

Tailors may specialize in anything from making simple alterations to measuring, designing, and creating bespoke suits from scratch. Most of the big-name clothiers produce something in between: made-to-measure suits, which are created to fit a client from a preexisting design. Couturiers’ fees range from several hundred to several thousand dollars, but assuaging the insecurities of powerful people comes at no extra charge.

Tailors see more than seams; they’re often privy to the innermost secrets of financial fashion plates. After all, if your C.F.O. trusts a guy to measure his inseam, just imagine what he’ll spill to the man holding the tape. So we asked a half-dozen tailors to tell us what it’s like helping corporate types learn to love the nickname “suit.”

Chris Ahern
The owner of Jack Christopher Custom Clothing in Baltimore, Chris Ahern custom-tailors suits for athletes and sports executives, and he once created a complete outfit for a client, even selecting the shoes and watch. A complete suit costs between $900 and $3,000; shirts range from $100 to $350; neckwear costs between $85 and $150.

Looking up: Guys want to be like the chief. When I walk into an office, I see the younger guys wearing clothing they can’t afford yet. They say, “I like the way you dressed C.E.O. Bob. Let’s do it like that.”

Dressing the part: If I’m seeing an N.B.A. player, I dress like they’d dress. If I’m seeing a C.E.O., I wear a dark, conservative suit, a repp tie, the old university look. When I was seeing some guys on the Chicago Cubs back around 1997, I felt like I was in the 1920s, 1930s. I had on a gangster-striped suit, black-and-white polka-dot tie, pocket square. I turn around, and Sammy Sosa says, “You look good, man. You look really good.”

The must-have: A navy blazer. It’s multi-functional. You can wear it with chinos, with gray, with olive—dress it up and dress it down.

The must-go: Nothing looks worse than a well-dressed guy in a pair of beat-up loafers.

Jessica PetersAstor & Black, a haberdasher based in Columbus, Ohio, sends its experts to homes and offices. Jessica Peters heads the New York branch. Her favorite tasks are helping older execs express their personalities and dressing up younger businessmen for dates. Suits range from $500 to $1,500.

Short on style: If they’re working on Wall Street, they send abbreviated messages, because stockbrokers have no time. They’ll come in and be like, “I trust your judgment. Buy me shirts and three suits—black, gray, blue.” And that’s it. On the other hand, at Goldman Sachs, they dress to impress.

Youth or beauty: For a young guy just starting out in business, I’d set him up with the basics—three Canali suits. If it’s an older guy, I’d suggest something with life to it that brings out his personality, like a fabric that doesn’t stand out from a distance but that up close is elegant without being distracting. I’d set a C.E.O. up with Scabal.

Black isn’t back: I try to steer them away from black. It’s too severe, just doesn’t seem right in a lot of situations. I like herringbone. If you wear it once a week, it’s not too loud, and all the others guys won’t say, “I saw you wear that before.”

Joel Diaz
The owner of Jolibe in New York, Joel Diaz has been a design consultant and tailor for more than 25 years. He specializes in custom tailoring for fashion houses (Helmut Lang is a client), celebrities, and the occasional executive. Diaz charges $120 per hour for design and consulting and $75 per hour for tailoring.

C.E.O. softies: Celebrities in the music field are always divas—they’re nice, but it’s got to be a certain way. Film people are nicer and more relaxed. Madonna really, really knows exactly what she wants. The C.E.O. of a company is like, “Well, what do you think?” They trust my judgment more.

Risk and return: I wish businesspeople would take risks with their clothes. They’re too uniform-like. There’s no difference from one guy to the next. I see guys go to the store and be at the mercy of whoever’s helping them. I like the sharpness of a suit—and it can be cheesy if you get too crazy—but I would fine-tune the details in suits, put a little color in the shoulders, just to let them stand out.

Tailoring in traffic: I was doing the Golden Globes in L.A. Ellen DeGeneres really loved this fabric, but it wasn’t available in the States, so we had to find someone in Italy to drive it to Paris, and then find someone in Paris who could fly it to Los Angeles—and the show was in like two days! So when it finally got there late at night, I had to make the suit in the back of an S.U.V. while the driver was driving really fast to get to the restaurant where Ellen DeGeneres was—also, it was her birthday. I got to the restaurant, but she didn’t like the light inside, so we went out in the boulevard in the middle of traffic, and I had to build her a suit as all these people in cars were laughing and joking with her. The next day, she said she wanted to fit it again because she might have been a little drunk the night before. The clients never have any idea what’s involved in making clothes the way they want them. She said the suit was perfect, though.

Olga Dudnik
A tailor since 1990, Olga Dudnik mainly does alterations for haute couture houses, movie stars, and fashion industry icons; her favorite clients are the ones who are about to hit megastardom but are still “real.” Her fee is $550 per day for an average project, with a minimum of a half-day for $315.
Expense account tailoring: If I’m working for the president of a business, I don’t know if it’s coming out of their pockets or if it’s deductible, but they are willing to pay about the same for an alteration as they’d pay for a new piece.

Tailor talk: You’re not the person their career depends on, you’re not underneath them, and you’re not the kind of person who’s going to take it out of the fitting room. Basically, they say things to you to get feedback in an earnest way. One entertainer likes to talk about her life and sexual experiences—not even necessarily about hers! She’s always talking, not really to you. Even if you’re not there, she keeps talking, like she’s talking to herself or just saying what’s in her head. But nobody talks about business—that’s for sure.

Role reversal: What’s hilarious is that these people in big positions in companies, whom you see as so confident and powerful when they’re in front of the tailor’s mirror, change suddenly when the tailor’s in charge. It’s a funny transition. Their confidence is gone, and they’re like, “Is that my arm, or is it sewn that way?” You have to be very gentle.