His first wife was Serena Healy, who died in childbirth on June 19, 1882. His second was Grace Alice Clark of Worcester, Massachusetts, whom Wallace met in Pasadena while she was vacationing there. They were married in Worcester about 1888, and after she moved to Los Angeles she became a charter member of the Ebell Club. They had four children, Kenneth Clark, Donald J., Helen Harriot and Katherine. She died on July 6, 1913. His third wife was Grace H. Wallace.