[1] Arnt was born in Michigan City, Indiana, the son of a banker.

While at Princeton, he helped to found the University Players[clarification needed] and was president of the Princeton Triangle Club theatrical troupe.

[2] In the early 1930s, Arnt acted with the University Repertory Theater in Maryland.

[2] On Broadway, he appeared in Carry Nation (1932), Three Waltzes (1937), and Knickerbocker Holiday (1938).

[3] In 1962, Arnt retired from acting and began to import and breed Charolais cattle on a ranch in Washington state.