Moroni Olsen was a renowned character actor, born in Utah to Mormon parents, Edward Arenholt Olsen and Marsha Holverholst. Raised in Utah, Olsen attended Weber State Academy, where he graduated, and later studied drama and elocution at the University of Utah.
Olsen's voice training at the University of Utah served him well in his future career, both on the Broadway stage and in Hollywood. He began his acting career in church theatricals and eventually organized The Moroni Olsen Players, a touring company that became one of the better-known repertory companies in the country.
Olsen made his Broadway debut in 1920, portraying Jason in "Medea", and continued to work in New York for the next couple of years, appearing in a series of classical plays. For the next eight seasons, he directed and coached his repertory Players, while also handling scenery, staging, and choreographing duties.
After a decade's absence, Olsen returned to Broadway in 1933 with "Her Man of Wax", followed by appearances in "Mary of Scotland", "Romeo and Juliet", and "The Barretts of Wimpole Street".