Was offered the role of either Peter Venkman or Egon Spengler in Ghostbusters (1984) but turned down both parts, which went to Bill Murray and Harold Ramis, respectively. Was originally slated to play Jeff Daniels character in Woody Allen' s The Purple Rose of Cairo (1985) and actually did film some scenes, but Allen decided it wasn't working and replaced him with Daniels. He had the same fate in Mystic River (2003) when he was cast in the role of Sean Devine, filmed some scenes but he and director Clint Eastwood had creative differences on the project and Keaton opted to leave the film. Was considered for the role of Jack Crawford in The Silence of the Lambs (1991). Was considered for the role of Dr. Curtis McCabe in Vanilla Sky (2001). Was considered for the role of Capt. Jack Sparrow in Pirates of the Caribbean: The Curse of the Black Pearl (2003). Was considered for the role of Lt. Col. Kazinski in Jarhead (2005).
His father had English, Scottish, Scots-Irish (Northern Irish), and German ancestry, while his mother was of Irish descent.
Appeared with the late Christopher Reeve in Speechless (1994). Keaton and Reeve played DC Comics two most iconic characters, Batman and Superman, respectively.
Was in a relationship with Courteney Cox (1989-1995).
His son, Sean Douglas, plays keyboard for a band called "The Hatch".