|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, showing Rosewood having and using excessive firepower and weaponry, as demonstrated by the line: "Billy, we gotta talk," used by Foley and Taggart. 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.
Billy is still at the police department working his partner John Taggart. A new boss is there and suspended Bogomil , hour latered he was gunned down he and Taggert headed to the hospital. He talks with Axel on the phone while Axel was trying to bust a deal. Later on in the film Taggart and him reunited with Axel Foley and Billy has a knife and heavy duty guns and every time that scenes come Taggart says "Billy we got to talk!" Billy and Taggart also help Foley to take down the Alphabet Crimes and find out Maxwell Dent is an arms dealer and the mastermind behind the Alphabet Crimes with his henchwoman Karla.
While Axel looks at Billy crazy and also he's a big fan of sly stalllone movies.
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).