William Galen McMaster was the son of C. A. McMaster and related to D.C. McMaster. He studied Agronomy at Iowa State College but left the Class of 1921.
He enlisted on June 1, 1918 at Twin Falls, Idaho. The army assigned him to Compnay C, 157th Infantry. His foreign service began around September 3, 1918. He was transferred to the 305th Infantry while stationed in France.
William was killed in action in the Argonne forest on September 27, 1918.