Harley A. Harmon was born in 1882 in Wier City, Kansas. His father, Elmer Harmon, was an attorney who moved the family to Los Angeles, California when Harmon was nine years old. In 1903, Harley A. Harmon unsuccessfully ran for Los Angeles City Clerk. In 1905, Harley A. Harmon joined the Union Pacific Railroad as an engineer and drove one of the first construction trains to Las Vegas, Nevada, where Harley A. Harmon was stationed in 1908.