He was in private practice in Los Angeles, California from 1933 to 1941.
He was a Special Attorney of the Antitrust Division of the United States Department of Justice in Los Angeles from 1942 to 1943.
He was an Assistant United States Attorney of the Southern District of California from 1943 to 1946, serving as Chief Assistant United States Attorney from 1946 to 1949.
He was the United States Attorney for the Southern District of California from 1949 to 1951.
Tolin received a recess appointment from President Harry S. Truman on October 30, 1951, to a seat on the United States District Court for the Southern District of California vacated by Judge Paul John McCormick.