He also appeared on the stage as Julian Dallas, spending a year with the Liverpool Old Vic, and in London under the direction of John Gielgud in The Cradle Song, among other plays.

Consigned mainly to action roles in Warner Bros. films such as Rocky Mountain (1950) and Operation Pacific (1951), Forbes played more in-depth characters on TV.

On 3 December 1959 Forbes appeared as a homesteader, Cass Taggart, in the episode "Rebel Ranger" of CBS's Dick Powell's Zane Grey Theater.

Joan Crawford is cast in this episode as Stella Faring, a Confederate widow from San Antonio, Texas, who tries to reclaim her former home and the birthplace of her son Rob (Don Grady), from the Unionist owner Taggart.

Character actor John Anderson is cast as Fisk Madden, who tries to drive Taggart off his land and gain Stella's favor.

After Jim Bowie ended its two-year run in 1958, Forbes returned to Great Britain, where he became a frequent guest star in television dramas.