Chicagoan Mark Gill knows his outspoken sense of styling isn’t for everyone. “If they want someone brutal, they’ll choose me,” says Gill, whose well-heeled clients pay him $500 an hour to dispense advice on how to dress. “If they want someone who will stroke them, that’s not me. I’m no-nonsense.” Gill, 42, has built his growing fashion-consulting business on that pointed opinion, one in such demand that he regularly jets from Chicago to New York, Washington, D.C., and Miami to help select perfect ensembles for his 20 clients, some of whom spend $100,000 on clothes and accessories every season.

Thanks to his Personal Wardrobe Planner software, which includes photos of all the elements of a client’s wardrobe—from coats and dresses to shoes—Gill can also assemble outfits without leaving home. And to assuage any anxieties, there’s always the phone.

“I need to have complete access to their wardrobes at all times,” Gill says of his clients, a mix of old-money philanthropists and high-powered executives such as Debra Lee, the chief executive officer of the Black Entertainment Television Network.

Gill, who makes his presence known with a booming laugh and a formidable voice (he’s a trained tenor), has not been without his missteps. One client informed him: “Mark, your eye is amazing, but I need you to listen. Most of my life is casual. You’re bringing me Giambattista Valli. I have children. I have a dog. I go to basketball games. I am a mom.” Scaling back his initial selections, Gill responded by mixing a Jil Sander T-shirt with Banana Republic trousers.

But there is no denying Gill’s love of luxury. He wore his first Giorgio Armani Black Label suit at age 18, and for his clients, he is currently enamored with Fendi, Yves Saint Laurent, Giambattista Valli, and Marc Jacobs’s ready-to-wear collection for Louis Vuitton.

With his eye on modern classics, Gill has no interest in the latest It bag carried by Lindsay Lohan. “I hate the influence of Hollywood,” he says. “Why would someone want to take on someone’s identity? That’s absolutely absurd. I could give a rat’s ass about trends. You have to know your client and their long-term goals. People come to me because they have a responsibility to look appropriate. It’s not to get the latest thing.”

Despite his strong assertions, Gill says his foray into fashion was somewhat unexpected. “It was never on my agenda,” he explains. Gill initially wanted to be an architect and received his bachelor’s degree in accounting from Webster University in St. Louis. He spent a handful of years in banking while also working part-time at Kinko’s and Banana Republic and studying with a vocal coach at DePaul University.

Then, during a full-time stint at Banana Republic on North Halsted Street in 1995, Gill flexed his fashion muscles and sold more than $1.8 million in merchandise in a year. And when a customer requested an in-home wardrobe and closet consultation, Gill began charging $50 an hour. In 1998, he left Banana Republic to become a sales specialist at Jil Sander on Oak Street, then started his own full-time consulting business in 2000.

Over the next eight years, Gill launched an upscale handbag line and extended his fashion reach to the East Coast. He also recently added a division to supply styling services to male executives. Meanwhile, Gill is not beyond relaying advice for free. For First Lady Michelle Obama, he advises, “Wear a suit sometimes; I haven’t seen a great suit yet.”

 And while he’s at it, here’s another edict:

“I hate nail polish,” Gill says. He claims that nail color can clash with an outfit and that most of his clients opt for a clear coat. “If you keep it nude, it goes with everything.”

Photograph: Taylor Castle