He served the remainder of the war as a military attaché in Washington, for which he was appointed to the Legion of Merit.
The son of George Ross Mackessack, he was born at Alves in the County of Moray and was educated in England at Rugby School.
[1] From Rugby, he attended the Royal Military College, Sandhurst, from which he graduated into the Seaforth Highlanders as a second lieutenant in February 1923.
[4] In that same month he played for Northern Punjab against the MCC, before making his final first-class appearance for the Europeans against the Hindus in March 1928.
[1] He was divorced from his wife in 1947, with Mackessack marrying Nora Joyce Edward-Collins in March of the same year.
[6] He retired from active service on account of ill health in January 1948, upon which he was granted the honorary rank of lieutenant colonel.