[3] On his mission, he met Dawn Houghton, which he later married, and decided to teach religion at Brigham Young University.
In 1959, he received an award from President Dwight D. Eisenhower, selected as one of four visually handicapped students in the United States.
[10] Cowan helped write the Sunday School manual for the Church of Jesus Christ of Latter-day Saints from 1978 to 1980, on the Doctrine and Covenants and LDS history.
[2] In 1972, the Church planned a new sixteen-volume sesquicentennial history to be published in 1980, and Cowan was commissioned to write about the 20th century.
[13] From 1981 to 1993, Cowan served as the chair of the committee in charge of preparing Gospel Doctrine lessons for the Church.
He was a co-editor with John P. Livingstone and Craig J. Ostler of The Mormons: An Illustrated History of the Church of Jesus Christ of Latter-day Saints, published in 2013.