Waldo Morgan Allen was a distinguished World War I officer and prominent community leader. Born in Orange, New Jersey, he hailed from a family with deep ties to Chicago—his grandmother, Elizabeth Downs, was an early settler, and his maternal grandfather, Calvin Durand, was a prominent grocer. Allen attended Lake Forest Academy and graduated from Yale in 1916, where he joined the Yale Battalion, later serving in the 10th Field Artillery of the Connecticut National Guard.

During WWI, Allen was among the first ROTC class at Fort Sheridan, Illinois, and rose to First Lieutenant in the 331st Field Artillery of the American Expeditionary Forces, training near Bordeaux. After the war, he edited a history of his regiment, then pursued a career with Durand, McNeil, and Horner Company.

A respected figure in his community, Allen served as Governor General of the General Society of Mayflower Descendants. At the start of WWII, he returned to active service as a major in the Organized Reserves, completing his assignment in 1942. He later lived in Lake Forest with his wife, Mary Penfield.