The timber and adobe house near Fruita, Utah, which came with the position, provided Kelly and his wife a home while he researched and wrote.
Kelly produced many articles for journals and periodicals, conducted research for projects by other historians, and engaged in a voluminous correspondence with others working in western history, including Dale Morgan and J. Roderic Korns.
Kelly's position safeguarding Capitol Reef extended into a twenty-year-long second career when, in 1950, he received a civil service appointment as the Monument's first superintendent.
During the 1950s Kelly was deeply troubled when NPS management acceded to demands of the U.S. Atomic Energy Commission that Capitol Reef National Monument be opened to uranium prospecting.
During the early 1920s, he briefly held a position with the Ku Klux Klan in Salt Lake and wrote about his anti-Semitic views.
He blamed this a trait on his father's example: On a personal level Kelly was considered kind and generous and had a number of loyal friends, but was often described as a misanthrope.
He famously posed for a picture thumbing his nose at the Mormon monument to the Mountain Meadows Massacre, claiming that Lee was a scapegoat and that higher-ups were responsible.