A Democrat, he served as a United States Senator from Michigan from 1959 until his death from cancer in Washington, D.C. in 1976.

[4] He received his early education at Waldron Academy, and then attended West Philadelphia Catholic High School.

[5] Hart studied at Georgetown University in Washington, D.C., where he was the student body president and an award-winning debater.

[3] In 1937, he received a Juris Doctor degree from the University of Michigan Law School at Ann Arbor.

Hart was admitted to the State Bar of Michigan in 1938 and became an associate in the Detroit firm of Beaumont, Smith & Harris.

[7] He was wounded during the D-Day invasion of Normandy on Utah Beach when shrapnel from an exploding artillery shell damaged the inside of his right arm.

[6] He was decorated with the Bronze Star Medal with clusters, Arrowhead device, Purple Heart, and Croix de guerre.

[3] In 1951 Hart was appointed as state director of the Office of Price Stabilization, serving for a year.

Hart is interred in St. Anne's Catholic Cemetery on Mackinac Island in a family plot near his namesake son, who died as a toddler.