A devoutly religious man himself, he twice played the head of a church: Pope Leo I in Sign of the Pagan (1954) and John Knox in Mary of Scotland (1936).
Appeared in three "Three Musketeers" films - the 1935 version with Walter Abel (The Three Musketeers (1935)), the 1939 comedy version with Don Ameche and the Ritz Brothers (The Three Musketeers (1939)), and a 1952 film called At Sword's Point (1952).
Distant relation of football legend/actor Merlin Olsen .
His given name, Moroni, comes from the name of a angel, who, according to an account by Joseph Smith, founder of the Church of Jesus Christ of Latter-Day Saints (Mormons), revealed to him the location of the document which would become known as the Book of Mormon.
It is often claimed that Olsen's real name was John Willard Clawson and that he was the son of Utah artist John Willard Clawson Sr.; however, this is not found in fact.
Moroni Olsen got his start on Broadway in "The Cat And The Canary" which he wrote and starred in under the pen name John Willard.
Strongly involved with Hollywood's annual Pilgrimage Play for many years as a director.