Born in Winnipeg, Manitoba, Kruschen began his radio career while still in high school, and during the 1940s, he became a staple of West Coast radio drama. He had several roles in programs made especially for the Armed Forces Radio Service (AFRS) broadcast for the benefit of members on active duty in the military in the 1940s and 1950s. He had regular or recurring roles on Broadway Is My Beat (as Sgt. Muggavan), and Pete Kelly’s Blues (as Red, the bass player), as well as frequent episodic roles on anthology series, Westerns and crime dramas. He was heard on such high-profile series as Escape, Dragnet, Gunsmoke (usually as law abiding locals), Crime Classics, Frontier Gentleman, Yours Truly, Johnny Dollar, Nightbeat and Suspense. His movie career is highlighted by his performance as neighbor Dr. Dreyfuss in Billy Wilder’s The Apartment (for which he received an Academy Award nomination for Best Supporting Actor). Other film assignments included George Pal’s The War of the Worlds (as Salvatore, one of the first three victims, a role he reprised on the Lux Radio Theater adaptation), in Cecil B. DeMille’s final film, The Buccaneer, as astronaut Sam Jacobs in the 1959 cult classic The Angry Red Planet, The Unsinkable Molly Brown (as saloon owner Christmas Morgan), Abbott and Costello Go to Mars, Lover Come Back, McLintock! (with John Wayne and Maureen O’Hara), Follow That Dream (with Elvis Presley), Cape Fear, starring Gregory Peck and Robert Mitchum, and Money to Burn with Eve McVeagh. Kruschen appeared as Maurice Pulvermacher in the original 1962 Broadway production of I Can Get It for You Wholesale with neophyte singer/actress, 19-year-old Barbra Streisand. In 1969, he co-starred in the London staging of the musical Promises, Promises, reprising his film role in this show based on The Apartment.

Kruschen was performing on television as early as 1939, appearing in dramas on Don Lee’s experimental television station in Los Angeles, where he was seen on some two hundred television sets with three-inch screens. In January 1959, Kruschen played a cutthroat, Sam Bolt, in the episode “The Desperadoes” of the ABC/Warner Brothers western series, Sugarfoot, starring Will Hutchins in the title role. Set at a mission in South Texas, Sugarfoot learns of a mysterious plot to assassinate Mexican President Benito Juarez. Abby Dalton and Anthony George guest starred with Kruschen in this episode as Elizabeth Bingham and Padre John, respectively. Thereafter, Kruschen’s television career included guest villain Eivol Ekdol, a villainous magicians’ craftsman on Batman (episodes 9 and 10). He also was seen in twelve episodes of NBC’s Dragnet (portraying a pedophile in one infamous episode) as well as the ABC/Desilu series, Zorro. He had a recurring role across three seasons on Bonanza (Italian grapegrower Giorgio Rossi,) as Tully the bartender in the 1960–1961 ABC series Hong Kong (that launched Aussie actor Rod Taylor into his film career). In 1969, Kruschen co-starred with Stefanie Powers in an unsold ABC sitcom pilot, Holly Golighty, adapted from Truman Capote’s Breakfast at Tiffany’s. The husky, mustachioed Kruschen seemed to specialize in playing benevolent ethnic paternal figures and had roles in Columbo (The Most Dangerous Match, 1973), Barney Miller, Odd Couple (TV series), Busting Loose, The Incredible Hulk, and, in later years, Murphy Brown, Lois and Clark: The New Adventures of Superman. He appeared in the recurring role of ‘Grandpa Papadopolis’ on the situation comedy Webster (1985 to 1987), and in the early 1990s, as another Greek grandfather and as Pam and Jesse’s grandfather ‘Papouli’ (‘Iorgos Katsopolis’) on Full House, appearing in only two episodes before his character dies in his sleep, in episode, ‘The Last Dance’. Kruschen’s final on-screen appearance was in the 1997 film ‘Til There Was You (with Sarah Jessica Parker), Dylan McDermott, and Jeanne Tripplehorn, as ‘Mr. Katz’.

Kruschen was married to Marjorie Ullman from January 1947 to 1961, and his second marriage was to Violet Rafaella Mooring from 1962 to 1978 (her death). He was married a third time to Mary Pender from July 23, 1979, until April 2, 2002, when he died in Chandler, Arizona, while vacationing. He had been in ill health for some time. He was 80. Though he died on April 2, his death wasn’t widely reported to the media, until late May 2002. He is survived by his third wife Mary Pender; his two children from his first wife Marjorie Ullman; his grandchildren; and a sister.