Gavan John O'Herlihy was an Irish-American actor. He was known for playing Chuck Cunningham in the first episodes of Happy Days, as well as his appearances in films such as Never Say Never Again, Death Wish 3, Willow, and Superman III.

Daniel Peter O'Herlihy was an Irish actor of film, television and radio. O'Herlihy's best-known roles included his Oscar-nominated portrayal of the lead character in Luis Buñuel's Robinson Crusoe (1954), Brigadier General Warren A. Black in Fail Safe (1964), Marshal Ney in Waterloo (1970), Conal Cochran in Halloween III: Season of the Witch (1982), Grig in The Last Starfighter (1984), "The Old Man" in RoboCop (1987) and its 1990 sequel, and Andrew Packard in the television series Twin Peaks (1990–91).