Best known as Dave Bowman in 2001: A Space Odyssey (1968), a role he revisited in 2010 (1984).
Both his parents have appeared in his movies. Father Robert Dullea appeared as the aged Marquis De Sade in the final scene of De Sade (1969). This was an add-on scene to the film: Keir didn't want to go through the old-age makeup, so he suggested they hire his father for the scene. This was done, Robert Dullea went to Germany, did the scene, and according to Keir, enjoyed the whole experience. Mother Margaret Ruttain Dullea appeared in a non-speaking role in David and Lisa (1962). She was going up a flight of stairs in the background of a scene between Keir and Janet Margolin.
Ex-wife Susan Lessans is married to former pro football great Don Meredith.
In 1983, Keir Dullea, with then wife Susie Fuller Dullea, founded the Theater Artists Workshop of Westport.
One of the last people to see Sal Mineo alive. They had just finished rehearsing for a play sometime before Mineo's murder.
Rumor had it that Paramount's planned production of "Dear and Glorious Physician" would star Keir Dullea in the lead role of St. Luke, but the cost of such a movie, coupled with fears that the Biblical "epic" had gone out of style, prompted Paramount to abandon the project in the mid-1960s.
Will be portrayed by Actor Jim Parrack in the upcoming biopic of Sal Mineo titled "Sal", directed by James Franco. Dullea and Mineo were in rehearsal for the play "P.S. Your Cat is Dead" shortly before Mineo was murdered in 1976.