Watkins served as district judge of the Fourth Judicial District of Utah 1928–1933, losing his position in the Roosevelt Democratic landslide in 1932. In the early 1930s, he served as the director of the Provo River Water Users Association and director of the Orem Chamber of Commerce. An unsuccessful candidate for the Republican nomination to the Seventy-fifth Congress in 1936, Watkins was elected as a Republican to the United States Senate in 1946, and reelected in 1952. He served from January 3, 1947, to January 3, 1959.