Mac was born Sept. 30, 1919, in Oshkosh, Wisconsin, to Sidney and Emma (Hall) Fell. He received his bachelor's degree in mining engineering from the University of Wisconsin in 1941 and worked for the Manitowoc Shipbuilding Company for 45 years. In 1944, he married Dorothy Mae Luecker of Manitowoc, and they raised three sons, Andrew, William, and Gregory.

Mac had a passion for photography and watercolor painting. He was an active member of St. Paul's United Methodist Church in Las Cruces. Mac was also involved with the Mesilla Valley Habitat for Humanity in Las Cruces since 1989, serving on the board of directors since 1990 and serving two one-year terms as president of the board. Mac documented build season after build season for us. Once he retired his hammer and picked up his camera, he captured countless photos and memories for Mesilla Valley Habitat for Humanity. He spent his summers in Eagle River, Wisconsin, at a cabin on the Chain of Lakes. Mac had been active in St. Paul's Methodist Church in Manitowoc, serving as chairman of the finance committee for 30 years, before moving to Las Cruces in 1987.