In 1966 Billington appeared in Incident at Vichy at the Phoenix Theatre in London, but was best known for his role as Colonel Paul Foster in the 1970 science fiction TV series UFO and for creating the character of Daniel Fogarty from 1971 to 1974 in the historical drama The Onedin Line.

Although he had some good roles, notably as Count Louis Dardinay in The Quest (1982), he did not reach the same level of success as he had in Britain.

He was screen-tested for the role of James Bond more than any other actor, and was said to have been Albert R. Broccoli's first choice had Roger Moore not been available (see: 1981's For Your Eyes Only).

Billington did a photo shoot for On Her Majesty's Secret Service, and met the film's director Peter Hunt.

His one Bond screen appearance was in the pre-title sequence of 1977's The Spy Who Loved Me, playing Agent XXX's ill-fated lover, Sergei Barsov.