After completing his mission in 1901, Smith began working in the office of the Church Historian and Recorder. In 1906, he was given the position of Assistant Church Historian. He wrote his first doctrinal book, "The Origins of the Reorganized Church and the Question of Succession" in 1909, to defend the LDS Church against the recent proselytizing by missionaries for the Reorganized Church of Jesus Christ of Latter Day Saints (RLDS Church) in Utah. He was the acting recorder of the 1910 general conference when he was called as an apostle. Prior to his call as a general authority, Smith served as the secretary and treasurer of the Genealogical Society of Utah. In 1921, Smith assumed the office of Church Historian and Recorder, which he held until 1970.