Claiborne was issued a train ticket home to Arkansas in 1945, but he instead opted to go to Las Vegas. Within a day of arriving, he secured a job as a patrolman for the Las Vegas Police Department. By 1947, he was admitted to the Nevada state bar and was working in the Clark County District Attorney's office. He was later the chief deputy district attorney for Clark County (1946–1948) and served as a state assemblyman in 1948. That same year he also served as city attorney for North Las Vegas.