During the 1970s served as a great "ham-fisted" foil to Clint Eastwood, appearing in four of Eastwood's films: The Eiger Sanction (1975), Every Which Way But Loose (1978), Thunderbolt and Lightfoot (1974) and Joe Kidd (1972). Usually Eastwood would pummel Walcott to a bloody pulp by the end of the picture.
Greg was introduced to his wife Barbara at a party by Hollywood legend, Dale Evans. Greg and Barbara had been married for 55 years when Barbara passed away on June 14, 2010.
Interviewed in "It Came from Horrorwood: Interviews with Moviemakers in the SF and Horror Tradition" by Tom Weaver (McFarland, 1996).
When he met Ava Gardner, he informed her that they came from the same hometown.