[4] When World War I commenced in 1914, MacDonald attempted to enlist in the Australian Army but claimed he was rejected due to having bad teeth.
[1] Upon his return to Tasmania in 1916, MacDonald attempted to enlist again and was successful due to what he believed to be the army's desire to quickly send more troops after large numbers of Australians had been killed while fighting in the war.
MacDonald later recalled that on one occasion he was tying a knot in a communication cable when eight shells exploded nearby causing the putty in his pocket to burn into his leg.
However, after the army decided he was too old to see action, MacDonald was relegated to the Victoria Barracks in Sydney where he served five years undertaking clerical work and providing administrative support during World War II.
[8] MacDonald along with fellow Tasmanian World War I veteran (and also the final surviving Australian Gallipoli digger) Alec Campbell were posthumously honoured on a commemorative plaque which was unveiled in front of two trees that had been planted in 1926.