Larson began serving as the assistant attorney general of Iowa in 1943. He was appointed as the state's attorney general in 1947 to fill the unexpired term of John M. Rankin. He was elected to the office in 1948 and served until 1953.[2]
In 1952 he turned down an opportunity to run for governor.[3]
In 1953, he was appointed to the Iowa Supreme Court by Governor William S. Beardsley. He served a six-month term as the Chief Justice in 1955.[3] He became the first permanent Chief Justice from 1959 to 1961.[2]
Notable cases
Katko v. Briney while an associate justice of the Iowa Supreme Court.