He made his 1941 film debut in the role of Dai Bando in How Green Was My Valley, a drama about a working-class Welsh family that won the Academy Award for Best Picture.

[2][3] During television's early years in America, Williams was in scores of series episodes, including the Adventures of Superman as a sadistic character in the 1952 episode "The Evil Three".

Williams played art collector Rufus Varner in the 1958 Perry Mason episode, "The Case of the Purple Woman", and appeared on the religion anthology series, Crossroads.

His later appearances were on Temple Houston, 77 Sunset Strip, The Wild Wild West, 12 O'Clock High, Bonanza, The F.B.I., Mission: Impossible, Mannix, The Donna Reed Show, Here Come the Brides and The Andy Griffith Show.

His remains are interred at Forest Lawn Memorial Park in Los Angeles.