Father O'Malley is sent to St. Mary's, a run-down parochial school on the verge of condemnation. He and Sister Benedict work together in an attempt to save the school, though their differing methods often lead to good-natured disagreements.

Youthful Father Chuck O'Malley led a colorful life of sports, song, and romance before joining the Roman Catholic clergy. After being appointed to a run-down New York parish, O'Malley's worldly knowledge helps him connect with a gang of boys looking for direction, eventually winning over the aging, conventional Parish priest.