Avery Clare Gilleo was born in Lakeview, Michigan on June 4, 1894, and died in Ft. Lauderdale, Florida in 1946. (Jan. 17, 1957?) He was the son of Clarence and Gertrude Gilleo, and later resided at 333 Sunset NW, Grand Rapids. Schooling included Central High School of Grand Rapids and a brief enrollment at Junior College. Gilleo joined the Michigan National Guard and while on active duty attained the rank of First Lieutenant [and Second Lieutenant], and after the war was given the rank of Captain. While in France, Gilleo served with the American Expeditionary Forces, 126th Infantry, 63 Brigade, 32 Division, Company K. Eleanore Alten (Dec. 1, 1896-Jan. 12, 1994) & Avery married after his return from the War, 1919. Eleanore was the eldest daughter of painter Mathias Alten.

Their son, M. Alten Gilleo (Mathias Alten Gilleo), was born May 20 1921 and died Nov. 14, 1980. He was a scientist with Allied Chemical Corporation in Morristown, New Jersey at his death. Their daughter, Anita Marie Gilleo, lives in Grand Rapids, and continues to attempt to set up an Historic House Museum for grandfather Mathias Alten's works and life. Avery was divorced from Eleanore 1927 and his second wife was Meta E. Baker.