Was one of four actors (with Jack Nicholson, Bette Davis, and Faye Dunaway) to have two villainous roles ranked in the American Film Institute's 100 years of The Greatest Heroes and Villains, as Max Cady in Cape Fear (1962) at #28 and as Reverend Harry Powell in The Night of the Hunter (1955) at #29.
Was the defendant in FTC (Federal Taxation Commissioner) v. Mitchum (1965), a famous taxation case in Australia, in relation to income earned in Australia while working there on The Sundowners (1960).
Was the inspiration for the Kurt Busiek's Astro City character "Steeljack".
While filming El Dorado (1966) Mitchum was amused by co-star John Wayne's attempts to play his screen persona to the hilt in real life. He recalled that Wayne wore four-inch lifts to increase his height and had the roof of his car raised so he could drive wearing his Stetson.