At age 16, Callis moved to Coalville in Summit County, where he worked in the coal mines for 11 years.

From December 1892 until June 1895, he served as a missionary in the British Isles, including time in the Liverpool Conference.

In 1908, Callis was called as president of the church's Southern States Mission, succeeding Ben E. Rich.

Callis became an LDS Church apostle on 12 October 1933, filling the vacancy in the Quorum of the Twelve created by the death of James E. Talmage.

"[2] Nephi Jensen, a fellow missionary who worked with him in Jacksonville, Florida, wrote: C. A. Callis in many respects [is] a very remarkable man.

A few years ago he was working in a coal mine in Utah, now he is a practicing attorney and has been admitted to the bar in two states.

He not only acquired a knowledge of law by self effort but read widely on general subjects and trained himself in the art of public speaking.

His wife's death, which had occurred in October 1946, deeply affected Callis, and he never fully recovered from that loss.

Callis died in Jacksonville, Florida, at the age of 81, the day after meetings were held to organize the church's first stake in the Southern United States.

"[10] “The greatest thrilling experience that you and I can ever have in our hearts will be on those occasions when deep down we receive the witness that our acts and our labors are approved by our Heavenly Father.”[11] "This is the world in which to cultivate righteous tendencies and just causes that will produce, in the world to come, results and harvests of perfection and heavenly fruit.