At the outbreak of World War II Prince volunteered to fight with the Canadian Army, and served from June 3, 1940 until August 20, 1945. He was a member of the Royal Canadian Engineers, the 1st Canadian Parachute Battalion, and the First Special Service Force formed by combining Canadian and American troops to train at Fort Harrison near Helena Montana forming what became known as the famous "Devil's Brigade." Prince, and the other men of this unit were chosen for their rugged outdoor backgrounds and received the most rigorous training schedule under live fire ever undertaken by an army unit. All members of this elite squad, similar to the American Green Berets startiing in the 1960's, were trained to be paratroopers and received intense instruction in stealth tactics, hand-to-hand combat, the use of explosives for demolition, amphibious warfare, rock climbing and mountain fighting, and as ski troops. They have been described as the best small force of fighting men ever assembled. As a member of the Devil's Brigade, Prince was involved in fierce combat duty and numerous dangerous missions in Italy and France.
Prince was awarded the Military Medal, for his heroics at Anzio, Italy in an event that in 1968 was turned into a Hollywood film titled The Devil's Brigade. It was at Anzio that his unit got the name "Devil's Brigade." The diary of a dead German soldier contained a passage that said, "The black devils (Die schwartze Teufeln) are all around us every time we come into the line." The soldier was referring to them as "black" because the brigade's soldiers smeared their faces with black boot polish for their covert operations in the dark of the night.
Prince was decorated again for his valor while fighting in France and in 1944 was summoned to Buckingham Palace in London, England where King George VI presented him with his Military Medal and on behalf of the American President, the United States Silver Star. In all, Tommy Prince was decorated nine times, the most of any aboriginal soldier in the war. With the end of the fighting, Prince was honorably discharged in June of 1945 and returned to his home in Manitoba where he set up a small, but successful business. He married Verna Sinclair, with whom he would have five children
In 1946 he was elected chairman of the Manitoba Indian Association. Entrusting his business to friends, Prince devoted a great deal of time working with government to improve the conditions for Native peoples. Unfortunately, his friends mismanaged his small business and he ultimately lost everything.
In August of 1950, Prince re-enlisted in the Canadian Army to fight with the United Nations troops in the Korean War. Re-instated with his previous rank of Sergeant, Prince was part of the first Canadian regiment to arrive in the war zone. For conduct during one of the toughest actions of the war, he was one of the ones awarded the United States' Presidential Unit Citation for distinguished service. Wounded in action, he received the Korea Medal and the United Nations Service Medal. Following the Korean truce, he remained in the army, working as an instructor of new recruits in Winnipeg until his discharge in 1954.
Adjusting to civil life had not been easy for Prince after WW II, but with painfully arthritic knees as a result of the long, harsh conditions during his military service, his capabilities were limited. Add to that the discrimination against the Native people and his life became increasingly difficult, ultimately ending in his estrangement from his family. In June of 1955, Tommy Price made the news for his heroism in saving a man from drowning at the Alexander Docks in Winnipeg. But his personal life kept deteriorating and alcoholism overtook him resulting in his final years being spent virtually alone, living in a Salvation Army hostel.
Prince passed away on November 25, 1977 at the Deer Lodge Hospital in Winnipeg, Manitoba and was interred in the Brookside Cemetery.
Since his passing, a number of honors have been bestowed in his name. Some of them are: