The actor who stars as a fictionalized version of himself in The Fresh Prince of Bel-Air is Will Smith.
The sitcom premiered on NBC on September 10, 1990, with Smith playing William “Will” Smith, a street-smart teenager from West Philadelphia. In the story, Will is sent to live with his wealthy aunt and uncle, Vivian and Philip Banks, in Bel-Air after a fight in Philadelphia. That premise also echoes Smith’s real public identity as the rapper The Fresh Prince.
The role was Smith’s television acting breakthrough. Before the show, he was best known as one half of DJ Jazzy Jeff & the Fresh Prince, whose music career had made him recognizable but had also left him facing serious tax debt. Producer Quincy Jones helped bring him into the television project, which became a six-season, 148-episode hit and launched his film career.
A common mix-up is confusing the actor with the character: “Will Smith” is both the performer’s real name and the character’s name, but the sitcom character is fictionalized rather than a literal documentary version of Smith’s life. Other familiar names in the question—James Avery, Alfonso Ribeiro and Joseph Marcell—played Uncle Phil, Carlton Banks and Geoffrey, respectively.