He also served as an officer in the United States Coast Guard during World War II, from 1941 to 1946.
Portsmouth voters elected and re-elected MacKenzie to represent them in the Virginia House of Delegates (part-time) from 1954 to 1958.
[2] MacKenzie assumed senior status on November 30, 1985, serving in that capacity until his retirement from the bench, on January 30, 1998.
[3] MacKenzie married Elizabeth Nash during World War II, and during their 61-year marriage they raised a son and daughter.
Mackenzie served as chairman of the Eastern Virginia Council of Boy Scouts in 1972-1972, and was also active in Trinity Episcopal Church, including service on the vestry.