Robert Bruce McCoy was born on September 5, 1867 in Kenosha, Wisconsin. Soon after his birth, his family moved to Sparta, Wisconsin where McCoy graduated from high school. He entered the University of Wisconsin-Madison in 1887 and graduated from the law school in 1891. He married Lillian Riege in 1893 and shortly thereafter opened a law office in Sparta. He also became involved in politics when he was elected County Judge of Monroe County for four terms, from 1897 through 1914. He also served several terms as mayor of Sparta.
In May 1895, McCoy enlisted in Company I, 3rd Wisconsin Infantry of the National Guard and within one year he was commissioned as a captain. He volunteered for service in the Spanish-American War and saw service in Puerto Rico. Following his discharge, he joined Company L of the 3rd Wisconsin as a captain. In 1907, he became a colonel and small arms practice inspector for the Wisconsin National Guard and he served in that capacity until 1913, when he was appointed a major in the Ordnance Department. In 1916 he was mustered into federal service until he resigned February 1917 to rejoin the Wisconsin National Guard. McCoy was commissioned a colonel with the 4th Wisconsin Infantry Regiment in July 1917 and took part in recruiting and organizing the unit. He went with them to train at Camp MacArthur, Texas where the Wisconsin National Guard was incorporated into the 32nd Division and, as part of the reorganization, McCoy was given command of the 107th Trains and Military Police. He shipped over to Europe in February 1918 saw command duty with the 125th, 128th, and 127th Infantry Regiments. McCoy saw action at Aisne-Marne, Oise-Aisne, Meuse-Argonne, and Alsace-Lorraine. He received the Distinguished Service Cross and the French Croix de guerre in recognition of his service.
Following his discharge from active service McCoy reentered the world of politics and ran, unsuccessfully, as the Democratic candidate for governor of Wisconsin in 1920. In December of that year, he received a commission as Brigadier General of the 64th Infantry Brigade. In July 1924, he was promoted to Major General of the 32nd Division.
McCoy passed away on January 5, 1926 at his home in Sparta. On November 19 of that year, the Wisconsin National Guard military reservation near Sparta was officially named Camp McCoy in his honor.
