|Portrayed by||Judge Reinhold|
|Profession||Police Detective Sergeant|
|Affiliation||Beverly Hills Police Department|
Billy was born in 1960 and joined the Beverly Hills Police Department in 1981. A good cop, Billy is known to go strictly by the book, and is not as tough as his partner, John Taggart.
In the first film, he was generally polite and bumbling, and not particularly competent at anything, until it was revealed toward the end of the film that he had excellent marksmanship with a pistol, the second film expands on this weapon proficiency. He made friends with Axel Foley and sticks up for him from his superiors. He and his partner John Taggart help Foley take down Victor Maitland who killed Foley's friend Michael Tandino.
In Beverly Hills Cop II, Rosewood has matured a bit more and come into his own as a detective, perhaps a bit too much due to his newfound obsession with weaponry and Sylvester Stallone, worrying Taggart and Axel enough to suggest numerous times, "Billy, we need to talk." Despite his quirks and longing for excitement, Billy is still a dedicated and good-hearted officer.
Billy has now been promoted to DDO-JSIOC and Sergeant. Billy is now a big shot. When Axel arrives to visit him, he reveals that his former partner, John Taggart, is now retired and living in Arizona. He also has a new partner in Jon Flint. He along with Flint refuses to believe that Ellis DeWald is dirty. However, he later joins the shootout against DeWald's men. He is later shot by one of the security guards, but he survives. He is later seen in a wheelchair aside Axel and Flint as Uncle Dave introduces a new addition to his theme park in Axel's honor, Axel Fox. Uncle Dave commended Rosewood, Flint and Foley for their service and saving his life.
- Billy Rosewood has posters in his apartment of Rambo: First Blood Part II (1985) and Cobra (1986), both starring Sylvester Stallone. Stallone's then-wife Brigitte Nielsen appears in the film as Karla Fry and Stallone was the original choice to play the lead in the original Beverly Hills Cop (1984). In fact, when Stallone was signed to star in Beverly Hills Cop (1984), he did a polish on the script that focused more on action and took away the comedic element. He changed the main character's name from 'Axel Foley' to 'Axel Cobretti'. When he eventually dropped out of Beverly Hills Cop (1984), he used the character's name and certain elements from his polish of the script for Cobra (1986).