In film, he is best remembered for his role as James Bond's friend, CIA agent Felix Leiter, in Goldfinger (1964).

In the United States, he was a regular in the CBS soap operas The Secret Storm and The Edge of Night and in the 1980s appeared in several of the Perry Mason revival TV films as District Attorney Jack Welles.

Linder was also a regular on the popular 1980s Canadian crime series Seeing Things, playing Crown Attorney Spenser.

During his career, he also had guest roles in episodes of a variety of other popular British, American and Canadian television programmes, including: The Forest Rangers, Doomwatch, The Littlest Hobo, Alfred Hitchcock Presents, Ironside, The Saint, Danger Bay, The New Avengers, The Secret Storm (as Peter Ames), and The Edge of Night as Senator Ben Travis #2.

Linder appeared as Inspector Cramer in the CBC 1982 radio dramatizations of Nero Wolfe short stories.