He received a bachelor's degree from the University of Utah, where he initially studied economics, but decided to change his major even though his close advisor Lowell L. Bennion urged him to let writing be just a free time activity.
Originally Hart would have gone to Oxford in 1939 but the outbreak of World War II postponed those plans.
Hart was a United States Naval intelligence officer during World War II.
Hart edited Minor Lives: A Collection of Biographies that was published in 1971 by Harvard University Press.
In December 1944 Hart married Eleanor May Coleman in Washington, D.C., they were sealed in the Salt Lake Temple the following August.