Young first read a copy of the Book of Mormon in 1830 when it was initially published. He thought highly of it and believed it answered many of his religious questions, but he cautiously wanted to make sure the Mormons were sincere and sensible in their faith. He listened to their traveling missionaries, visited a Mormon congregation in Pennsylvania, prayed with them, was persuaded of their biblical focus, and submitted to baptism in 1832. He and a friend immediately traveled to Kirtland, Ohio, to meet the Mormon leader, Joseph Smith, Jr. Young found the 26-year-old prophet to be intelligent, straightforward, well schooled in the Bible, and a genial person. Impressed with the Mormon gospel and its leader, Young, as with many early converts, abandoned his shop and began a series of preaching missions in New York, Pennsylvania, New England, and upper Canada. He returned to the Mormon headquarters in Ohio, where he alternated between preaching in nearby areas and working on the construction of the Mormon temple in Kirtland, which was dedicated in 1836.
In 1834 Young married Mary Ann Angell. That year he joined some two hundred other men in marching with Smith to Jackson County, Missouri, to wrest control of Mormon lands from the anti-Mormon mob that had driven the Mormons out. Although Zions Camp, as it was called, did not achieve its goals, Young learned valuable lessons in how to organize and manage a group of people on the march.