In *Frasier*, Frasier has just left Boston when he returns to Seattle. The sitcom begins after the end of *Cheers*, where Frasier Crane had lived and worked as a psychiatrist and where his marriage to Lilith Sternin had ended.
Frasier moves back to Seattle because it is his hometown and because he wants a fresh start. He takes a job hosting *The Dr. Frasier Crane Show* on KACL, a fictional Seattle radio station. The move also brings him back into the lives of his father, Martin, and younger brother, Niles.
A common mix-up comes from the show's later geography. Frasier eventually spends time in Boston again during the episode “Cheerful Goodbyes,” while the original series finale involves possible work in San Francisco and a flight toward Chicago. Those later destinations are not the city he left at the start.
The question refers to the original series, which ran for 11 seasons from 1993 to 2004. Its premise is built around Frasier leaving the *Cheers* setting in Boston and relocating to Seattle.