John Sad began his practice of law in Cooperstown around 1914 and continued until approximately 1928, when he moved to Valley City to continue his practice there. While in Cooperstown he served as State's attorney from 1918 through 1924. He was for a time in partnership with M.W. Duffy.
In December 1951 he was appointed a District Judge of the seven-county First Judicial District with chambers in Valley City.
Source: Cooperstown, North Dakota 1882-1982 page 20