[2] Born in Boise, Idaho, McFadden went to high school in Hailey, did pre-law studies in Pocatello, and attended the University of Idaho College of Law in Moscow for two years.
[3][4] McFadden then became a court reporter for judge Doran Sutphen of the Idaho 4th Judicial District, in Gooding, under whom McFadden continued his legal studies, gaining admission to the bar in Idaho in 1940.
[3] He then entered the practice of law in Hailey,[5] leaving for two years to serve in the military during World War II, from 1944 to 1946.
[5][3] After the war, McFadden returned to Hailey, and the following year, after the death of his father, was elected to the position his father had held of Blaine County prosecutor.
[3] In 1959, Governor Robert E. Smylie appointed McFadden to the Idaho Supreme Court; the seat was vacated by the death of Chief Justice James W.