At 6'7" Megowan was very active in sports, playing baseball, football, and throwing discus.

He went to the University of Southern California on a football scholarship before serving in the U.S. Army during World War II.

[1] Megowan starred in the science fiction films The Werewolf in the role of Sheriff Jack Haines,[2] in The Creation of the Humanoids (1962) as a captain in the anti-robot Order of Flesh and Blood, who must stop the Humanoids,[3] and in The Creature Walks Among Us as the Gill-man.

[4] Megowan also appeared in Westerns: Davy Crockett, King of the Wild Frontier (1955), The Great Locomotive Chase (1956), Snowfire (1958), Tarzan and the Valley of Gold (1966), The Devil's Brigade (1968), and Mel Brooks Blazing Saddles (1974).

He guest starred in various programs, including the Westerns: Gunsmoke, Wagon Train (twice), The Californians, The Tall Man, Maverick, Cimarron City, Have Gun–Will Travel, Tales of Wells Fargo, The Rifleman, Lawman, Cheyenne, Colt .45, Bonanza, The Americans, Rawhide, and Daniel Boone.