Donald Knight was an English-born film, television, and stage actor. He worked largely in the United States, and often played tough guys.

The Immortal is an American television series, starring Christopher George as a man whose blood chemistry and resistance to almost all diseases makes him both almost immortal and a target of several wealthy men who would basically use him as a personal blood bank, aired on ABC from September 24, 1970, to January 14, 1971. The series is based on a pilot film of the same name, which aired on September 30, 1969, as an ABC Movie of the Week. The pilot is based on the 1964 science fiction novel The Immortals, by James Gunn.