One of three missionaries to open South Africa to the preaching of the gospel.
Walker, a member of the Mormon Battalion, joined five men who returned east at Green River to help guide oncoming companies. He joined with his wife to travel to Salt Lake Valley in the Spencer-Eldredge company in 1847. He was re-baptized at Salt Lake City on 11 September 1852. In 1857 he captained his own company of Saints emigrating to the valley.