He joined the U.S. Navy in World War II and was awarded a Distinguished Flying Cross and four Air Medals as a night fighter pilot.

[1] On his death, writer-director Norman Corwin told the Los Angeles Times Idelson was "a luminary, he stood out among the radio comedians.

[citation needed] He also had the title role on Cousin Willie[3] and portrayed Bill Clark on Secret City,[3]: 299-300  Hugo on The Trouble with the Truitts,[3]: 339-340  and Chuck on That Brewster Boy.

[4] In The Dick Van Dyke Show Idelson played Herman Glimscher, the milquetoast boyfriend of Sally Rogers (Rose Marie).

Idelson guest starred on episodes of Dragnet, The Twilight Zone, My Favorite Martian, The Odd Couple, Happy Days, Perry Mason and Will & Grace, in which he appeared along with his wife and daughter.