Moroni Olsen was the only principal cast member who was a Mormon. Dean Jagger was not a member of that church when he portrayed its leader, but he did join some 32 years later.
According to a MovieTone newsreel, the Salt Lake City premiere of Brigham Young, a month before the New York premiere, was the largest premiere in film history. 215,000 people crowded the streets of Salt Lake City to view a massive parade, complete with floats and racing cars with the stars riding in them. Twentieth Century Fox's studio head Darryl F. Zanuck, also the producer of the film, had a part in planning the parade. The Salt Lake City Mayor named that August 23rd Brigham Young Day- the first and only. Originally, one theatre in Salt Lake City was to show the film, but the demand for seats became so high that eventually seven theatres in the city showed the film.
A technician on the shooting said later that Henry Hathaway was a dictator-like man; working with him was like having a rattlesnake in one's pocket. Everyone had to be very careful about everything to avoid his wrath.
Linda Darnell said that she did not appreciate the shooting of this movie. She felt alone whilst Henry Hathaway and Tyrone Power stayed on their side, away from her. She also added that the overall atmosphere on the set was hard work and dirt everywhere.
Charles Halton is in studio records/casting call lists for the role of "Prosecutor," but that role was played by Marc Lawrence.