Michelle Doris Thomas was born on September 23, 1968, in Brookline, Massachusetts. She was the daughter of Phynjuar "Penwah" Thomas, a stage actress who also served as her acting coach, and Dennis "Dee Tee" Thomas, a musician and founding member of the band Kool & the Gang.

Growing up in Montclair, New Jersey, she graduated from West Essex High School in 1987. From an early age, she was involved in the arts, frequently accompanying her mother to theater rehearsals and performances. She was crowned Miss Talented Teen New Jersey and later won the Miss Talented Teen International title in 1984.

She started her acting career in 1983 with television commercials and appeared on Soul Train in 1984. She gained widespread recognition for her role as Justine Phillips, the girlfriend of Theo Huxtable, on The Cosby Show from 1988 to 1990.

She appeared in other TV programs, including A Man Called Hawk and Thea, and in films such as Dream Date (1989) and Hangin' with the Homeboys (1991). Her most notable role came as Myra Monkhouse, the girlfriend of Steve Urkel, on Family Matters from 1993 to 1998. In 1998, she joined the cast of the daytime soap opera The Young and the Restless, playing Callie Rogers Stark.

Michelle Thomas also appeared in music videos for artists like Mint Condition, Chubb Rock, and Dru Hill and guest-hosted the music series Soul Train in 1996 and 1997.

In August 1997, she was diagnosed with a rare form of stomach cancer. Despite undergoing surgeries and treatments, she passed away on December 23, 1998, at the age of 30 in New York City.

Just before her death, she had been nominated for an NAACP Image Award for Outstanding Actress in a Daytime Drama Series.