Jack Whalen
Freelance contract killer and bookie from the United States
About Jack Whalen
Lived 1918 – 1959 (aged 41). Jack Whalen was an American murderer and bookmaker.
Jack Whalen (May 11, 1918 – December 2, 1959), also called Jack O'Hara and "The Enforcer," was a criminal and freelance contract killer and bookie, who worked for the Los Angeles crime family, although he also was associated with Benjamin "Bugsy" Siegel, the Shannon brothers (Joe, Izzy, Moe, and Max) and Mickey Cohen during the 1940s and 1950s.
Life Jack F. Whalen was born in Missouri on May 11, 1918. Whalen's father, Fred—who was also a career criminal—had enrolled Jack in military school to give his son a better life. Jack played polo in school and piloted bombers in World War II. After the war, he married into a rich family in Los Angeles; however, by 1955, his own criminal career had begun. He was soon called "The Enforcer" because he was "so tough he didn't need a gun."
Death
On December 2, 1959, Whalen was shot "square between the eyes" and killed at Rondelli's restaurant in Sherman Oaks in the presence of Mickey Cohen and three other of his associates. Sam Frank LoCigno, although claiming self-defense, was charged with, but later acquitted of, the murder. Whalen was 41 years old at the time of his death.
In popular culture Whalen is depicted in the 2013 film Gangster Squad by actor Sullivan Stapleton. Whalen is also a featured character in James Ellroy's novel L.A. Confidential; as part of the power struggle for Mickey Cohen's criminal empire against gangster Morris "Mo" Jahelka.
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Important facts
People in Jack Whalen's life
Named in this biography and alive at the same time
Contemporaries
People whose lives overlapped Jack Whalen's
Frequently asked questions
Who was Jack Whalen?
freelance contract killer and bookie from the United States
When was Jack Whalen born?
Jack Whalen was born on 11 May 1918 in Missouri.
When did Jack Whalen die?
Jack Whalen died on 2 December 1959 in Sherman Oaks.
What was Jack Whalen's occupation?
Jack Whalen was a murderer and bookmaker.
What nationality was Jack Whalen?
Jack Whalen was American.
Sources & further reading
Cite this page
APA: Biography.guide. (2026). Jack Whalen. https://biography.guide/jack-whalen/
MLA: "Jack Whalen." Biography.guide, https://biography.guide/jack-whalen/.
Chicago: "Jack Whalen." Biography.guide. https://biography.guide/jack-whalen/.
Data last updated: 2026-09-20 · Spot an error? Report a correction.
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