Forester, Clarence Michael was born the 7th of November 1915 at Alfred, North Dakota. His father died when he was a young child, and his mother supported the family running a restaurant and taking in laundry. Forester left home at age 13 to work on a farm, and at age 15 came to Minneapolis.

He sailed from United States on the 10th of April 1937 aboard the "Rotterdam" and arrived in Spain in May 1937. In 1937 and 1938, Forester was a member of the Abraham Lincoln Brigade, a group of 3200 American volunteers who fought in the Spanish Civil War for the Loyalist government against a military insurgency led by General Francisco Franco. They, with other young men from non-Spanish countries, made up the International Brigades. Forester served as driver with the 11th International Brigade, with the 13th International Brigade in the Front of Córdoba, in Regiment of Trains, in the Auto Park of Albacete and with some Republican artillery units. He returned from Spain on the 15th of December 1938 aboard the "Paris".

During World War II, Forester served with the United States Army, participating in the drive across France and Germany. He was a member of the 188th Field Artillery Battalion.

Forester returned to Minneapolis after the war, where he worked factory jobs and as a machinist. He retired around 1983.

In November 1996, Forester and others 380 International Brigade volunteers, including 70 members of the Abraham Lincoln Brigade, traveled to Spain as guests of the Spanish government on the occasion of the 60th anniversary of the formation of the International Brigades and as a tribute to their unsuccessful struggle to defend the Spanish Republic against fascism. The veterans were made honorary citizens of Spain.

He died on the 1st of December 2004 in Minneapolis, Minnesota.