He has had a fashion business in New York since the late 1980s, the same decade that Michael Kors and Donna Karan started their namesake lines. He was inducted into the Council of Fashion Designers of America in 1998. From 1999 to 2018, he showed two collections each year, some on the schedule at New York Fashion Week.

But Michael Brown, 66, and his brand, B Michael, are not household names. While the designer, who goes by B Michael, has made capsule collections for Saks Fifth Avenue and has sold other pieces at a few specialty stores, many of his clothes have never been offered to the masses.

For most of his career, B Michael has focused on made-to-order pieces — some everyday items, and others for red carpets, galas or photo shoots. He describes his aesthetic as “modern day Audrey Hepburn.” Beyoncé, Halle Berry, Whitney Houston, Diahann Carroll, Lena Horne and the jazz singer Nancy Wilson have all worn B Michael clothes.

Some designs have gained outsize attention, like a floppy hat that the actress Cicely Tyson, who died in 2021, wore to the singer Aretha Franklin’s funeral. (Early in his career, B Michael designed hats for the TV show “Dynasty.”) After the service, the designer said, Ms. Tyson told him it was the first time in her life that she had been “upstaged by a hat.”

B Michael’s friendship with her is the subject of his new book, “Muse: Cicely Tyson and Me: A Relationship Forged in Fashion,” which was released in January. It chronicles the bond they built through clothes and it features dresses he made for the actress, including a gown she wore to the 2013 Tony Awards that drew comparisons to a purple scrunchie.

He describes his work as a version of haute couture, a term that technically can be used only by fashion houses granted permission by the French Ministry of Industry. After creating a full collection of sample garments, he said, “my private clients come and I build a muslin and we do multiple fittings.” As a Black designer making this type of clothing, he added, he has been sought out by some Black customers who had the means to buy couture but might not have had access to it.

The actress Phylicia Rashad, 75, has been a client since 2015. She said that what most appealed to her about the designer was not his race or ethnicity, but his work ethic.

“He’s a great designer,” she said. “Period.” Ms. Rashad added of his process, “He doesn’t work so much from pattern as from inspiration, and from inspiration, he creates that pattern.”

Dawn Davis, 57, a publisher at Simon & Schuster and the former editor in chief of Bon Appétit, said she has been wearing B Michael clothes for two decades. Ms. Davis, who is Black, described the items she bought as investment pieces. “Those purchases felt like splurges at the time,” she said. “But if I were to amortize the costs over 20 years, I would say they are worth the investment.”

Ms. Davis declined to comment on how much she has paid for B Michael clothes, and Ms. Rashad declined to comment when asked if she paid for her items. B Michael declined to comment on how much he charges for pieces, saying he will “never kiss and tell.”

“The women who buy my clothing wear Chanel, Valentino, Dior, so I compete with them,” he said.

Peter Arnold, who was the executive director at the C.F.D.A. when B Michael was inducted into the organization, said it is notable that he has maintained his business in an industry that can chew people up and spit them out. “I think that really speaks to the appeal of what he does and his own personal appeal,” said Mr. Arnold, who is now the executive director of the Fashion Scholarship Fund. B Michael garments have always had a “clear and distinctive” perspective, he added.

The designer Tracy Reese, who is Black and who started her eponymous fashion business in New York in 1996, described B Michael as “under the radar.” She said the designer had not received enough credit for the business he has built.

“A lot of times when you do a lot of custom work and red carpet, the dollars and cents don’t always work out,” said Ms. Reese, 59. “Michael’s had a really long and lucrative career.”

B Michael said he has maintained his business by staying focused and authentic to his point of view. “I always put out a collection and always manage to get to the next season,” he said. “And that’s what’s important.”

Born and raised in Connecticut, he cut his teeth making hats for designers including Oscar de la Renta and Louis Féraud after attending the Fashion Institute of Technology. In 1989, he started his own millinery line, and 10 years later, he shifted his focus to clothes. Though he had been involved in the fashion industry for more than a decade by then, B Michael described himself as an outlier at the time.

The industry “was not ready to embrace a Black American designer doing high-end luxury,” he said, and it was challenging to get the type of media attention that small brands rely on for visibility. “We all know about the struggles,” he said of being Black in fashion. “But I think that conversation could be had with the people who created them.”

Since 2010, he has run his business with Mark-Anthony Edwards, the chairman and chief executive of B Michael, and the designer’s husband of about a decade. (They married in 2014.)

“I completely just focus on the business of it all,” said Mr. Edwards, 52. “And he does what he does so beautifully,” he added of his husband.

B Michael said his business had angel investors in the past, but he declined to comment on whether it currently has investors. He has never received acquisition offers, he said, and has never had a “huge machine” behind his brand, which shrank during the pandemic. Aside from Mr. Edwards, he works with a pattern draper and a media director at his studio in Manhattan.

There are plans for the brand to expand into e-commerce, B Michael said, and he is developing a ready-to-wear line inspired by his made-to-measure clothes. “I will be paying attention to fit and detail, using great fabrications so that the ready-to-wear is still reflective of my point of view,” he said.

B Michael, reflecting on his career, said his intention was always to have a successful business. “Design is subjective, fashion is subjective,” he said. “It’s really about understanding the business model.”

More recently, though, he has been driven by another motivation. “Now it’s a personal thing for me to be a legacy brand as a Black American designer,” he said.