From 1923-39 he acted in several Broadway stage productions, including Gods of the Lightning, The Big Blow, and Within the Gates.
Before signing with Paramount Pictures in the 1930s, Nussbaum had already changed his last name to Ankrum. Upon signing with the studio, he chose to use the name "Stephen Morris" before changing it to Morris Ankrum in 1939.
In the sci-fi genre, he appeared in Rocketship X-M (1950), Flight to Mars (1951), as a Martian, Red Planet Mars (1952), playing the United States Secretary of Defense; the cult classic Invaders From Mars (1953), playing a United States Army officer; and as an Army general in Earth vs. the Flying Saucers (1956). In 1957 he played a Psychiatrist in the cult sci-fi classic Kronos and had military-officer roles in Beginning of the End and The Giant Claw.
On October 15, 1957, Ankrum had a major part in the episode "Strange Land" of the ABC/Warner Brothers western Sugarfoot, starring Will Hutchins. Ankrum played an embittered rancher named Cash Billings, who allows a hired gunman, Burr Fulton ( Rhodes Reason), to take over his spread, but Sugarfoot arrives to bring law and justice to the situation. Jan Chaney appears in the episode as Billings' daughter Anne, who takes a liking to Sugarfoot. Ankrum appeared again, as John Savage in 1959, in the Sugarfoot episode "The Wild Bunch". In 1961, he again played an embittered and this time paralyzed rancher, Cyrus Dawson, in the episode "Incident at Dawson Flats" of the ABC/WB western series, Cheyenne, with Clint Walker in the starring role, with other guest-starring parts for Jock Gaynor, Joan O'Brien, Gerald Mohr, and Hampton Fancher.
In the 1958-59 season Ankrum appeared 12 times in Richard Carlson's syndicated western series Mackenzie's Raiders, along with other cast "Raiders" Brett King, Jack Ging and Louis Jean Heydt. In the series set on the Rio Grande border, Carlson plays Col. Ranald Mackenzie, who faces troubles from assorted border outlaws.
Ankrum was cast in an episode of the 1959 CBS sitcom Dennis the Menace. He also made occasional uncredited appearances in several Roger Corman films. While busy in films and television, Ankrum was still involved in live theatre and continued to direct plays at the Pasadena Playhouse.
On September 2, 1964, Ankrum died of trichinosis. At the time of his death, he was still involved with Raymond Burr's Perry Mason series. His final appearance on Perry Mason, "The Case of the Sleepy Slayer", and his last film, Guns of Diablo, in which he was cast as Ray Macklin, were released in 1964 and 1965, respectively, after Ankrum's death.
