Moss made two memorable appearances in Bob Hope films, as Hope's Casablanca contact in the espionage spoof for a combined total of 124 performances, the longest run of the play in Broadway history.
He was also the first voice of the character of Ted White on the radio serial, The Guiding Light, from April 1948 to May 1949. Moss appeared on Star Trek as mysterious actor Anton Karidian, alter-ego of the tyrannical Gov. Kodos of Tarsus IV, in the episode "The Conscience of the King".
He appeared in the original Broadway production of the Hal Prince/Stephen Sondheim musical Follies, playing impresario Dimitri Weismann. He also played in The Rifleman as the school teacher, Mr. Griswald, and as Chief Lonespear in Bonanza episode "In Defense of Honor" in 1968.
His son was songwriter Jeff Moss.
Arnold Moss died from lung cancer aged 79 in New York City on December 15, 1989.