After attending college and law school, Minton served as a captain in World War I, following which he launched a legal and political career. In 1930, after multiple failed election attempts, and serving as a regional leader in the American Legion, he became a utility commissioner under the administration of Indiana Governor Paul V. McNutt. Four years later, Minton was elected to the United States Senate.

As part of the New Deal Coalition, the fiercely partisan Minton championed President Franklin D. Roosevelt’s unsuccessful court packing plans in the Senate and became one of his top Senate allies.

After Minton failed in his 1940 Senate re-election bid, Roosevelt appointed him as a judge to the United States Court of Appeals for the Seventh Circuit. After Roosevelt’s death, President Harry Truman, who had developed a close friendship with Minton during their time together in the Senate, nominated him to the Supreme Court. He was confirmed by the Senate on October 4, 1949, by a vote of 48 to 16, 15 Republicans and one Democrat voting against him. He served on the Supreme Court for seven years.

An advocate of judicial restraint, Minton was a regular supporter of the majority opinions during his early years on the Court; he became a regular dissenter after President Dwight Eisenhower’s appointees altered the Bench’s composition. In 1956, poor health forced Minton’s retirement, after which he traveled and lectured until his death in 1965.