As a child, he acted in his church's theater group, and at age 15, while participating in the Pentecostal Delman Heights Four Square Gospel Church choir, became interested in ministry. He graduated from San Bernardino High School in 1967 and briefly took up work as a janitor to save money for college. Thomas earned a scholarship to the predominantly black Oakwood College in Huntsville, Alabama, where he studied religion and philosophy after high school.

After two years at Oakwood College, Thomas transferred to the University of California, Riverside. During this time, he auditioned for and won a role in the San Francisco cast of Hair, which began his acting career. Thomas ultimately quit school to pursue acting as a profession, appearing in several features during the 1970s - including the classic black musical drama, Sparkle (1976). His big break came in 1984, when he landed a starring role in the popular television series, Miami Vice, alongside Don Johnson.

Thomas performed the title song of the album during the 1985 Miami Vice episode, "The Maze." The episode "Trust Fund Pirates" featured another of his songs, "La Mirada". Thomas' Miami Vice costar Don Johnson recorded an album shortly afterward titled Heartbeat. In 1987 Thomas recorded a song called "Ever and forever" with singer Lucía Galán.

Thomas is a vegetarian, nonsmoker and nondrinker. In 1986, Thomas married Kassandra Thomas. They have five children together (Noble, Kharisma, Sovereign, Sacred, and Imaj). In 1998, Thomas and Kassandra divorced. Thomas also has six other children (Sacha, Khrishna, India, Gabriel, Chayenne, and Melody) from previous relationships.

Thomas followed up in 1988 with a second album, Somebody. It also failed to produce a hit and sold poorly. In 1993, Thomas teamed with Kathy Rahill to compose "My, My, My, Miam...I", which was chosen as the city of Miami's theme song. That same year, Thomas teamed with Jamaican fitness instructor Sandi Morais to compose songs for a family-friendly musical titled Sacha, which enjoyed runs in south Florida and New York. The two formed the Magic Cookie Production Company. Thomas produced the music for Morais' fitness videos in 2001 and 2006.

In 1994 Thomas signed an agreement with Florida-based Psychic Reader's Network (later known as Traffix, Inc.) to become the spokesman for the Philip Michael Thomas International Psychic Network. He appeared in television ads and claimed to have met the planet's premier psychics through his "world travels". He dressed similarly to his Miami Vice alter ego, even opening the ads with the phrase, "From Miami Vice to world advice!" He appeared in informercials with Eileen Brennan and Todd McKee and his daughter, Sacha Nicole, to promote the psychic line. Thomas even released a cassette of music tied to his psychic Business titled PMT Psychic Connection, Volume I.

In 1997, Thomas was reunited with Don Johnson in the police drama Nash Bridges. He played Cedrick "Rick" Hawks, a U.S. Postal Inspector from Miami visiting Bridges (Johnson) in San Francisco. His first appearance was in the episode "Wild Card", and his second and final appearance was in the episode "Out of Miami", aired in 2001 during the program's final season.

He performed a voice-over in Grand Theft Auto: Vice City (2002) (VG) as Lance Vance, a main character who is trying to avenge his brother, Victor Vance's death. He reprised the voice-over role in the prequel Grand Theft Auto: Vice City Stories (2006) (VG) which details Lance's arrival in Vice City, his Business with drugs, and his relationship with his brother. After his work on the videogame of 2006 GTA: Vice City Stories Philip decided to retire from the acting, currently there is no news about Philip after his retirement.