Hyrum Jenkins Smith was born in Salt Lake City, Utah on 18 October 1914. His grandfather was Joseph F. Smith who presided over the L.D.S. church from 1901 until his death in 1918. Hyrum graduated from LDS high school in 1931 after which he contimued his educational pursuits at Brigham Young university where he earned a B.A. as a marketing major in 1938 and a M.A. specializing in transportation during the following year. In 1941 Hyrum married Leah Cannon with whom he raised a family of seven children. They were divorced in 1961 and in the same year Hyrum married Lucille Burrows. Smith spent four years in the United States armed forces from 1941 until the end of World War II. Subsequent to his discharge, Smith commenced a thirty-nine year career working in the private and public spheres. From 1964 until his retirement in 1984 Hyrum was the president of the Utah State branch of the National Federation of Federal Employees.

An active member of the LDS church, Smith was called in the summer of 1935 to serve as a missionary in the Swiss-German mission. During his two year mssionary stint, Hyrum corresponded with his parents and siblings. These letters reported not only his activities and reflections on his missionary experience, but also provided a commentary about living under a Nazi dictatorship. Initially Hyrum expressed his approval of Hitler's military and economic policies, such as the rearmament of the Rhineland. He agreed "wholeheartedly" with the Fuhrer's argument that German nation had a right to defend itself from potential foreign aggression and was convinced that Hitler was not preparing for a war against his adversaries. Deeming the end of the Nazi Four Year Plan as a success, he stated that "the streets are certainly beautiful with the party flags flying from nearly every window." Gradually he became disenchanted from with fascist rule noting that L.D.S. missionary endeavors were hampered in a variety of ways. Street meetings were banned, tracting activities were inhibited, and Mormons could not utilize the radio and window posters to promote their cause. Smith opined that for many Germans the Nazi regime was regarded as their religion. Noting that Hitler was conducting a campaign against numerous religious institutions, Hyrum expressed apprehension that the future of the L.D.S. faith in Germany might be in peril. He advised his correspondents to send their missives to him via registered mail because it was well-known that the German post office officials were opening and reading all incoming letters. While residing in Stuttgart and Cologne, Smith mentioned that Nazi authorities threatened foreigners with a seizure of their camera film if photos were taken of militarily sensitive objects which the Nazis believed could be used by the intelligence services of Germany's enemies. On his peregrinations throughout Germany, Hyrum took photos of anti-Semitic public signs and on one occasion photographed Hitler speaking at a Nazi street rally and afterwards showing the German dictator departing from that event in a government car.

Hyrum Jenkins Smith died on 4 June 1999 in Salt Lake City.