James McDonald enlisted in the United States. Navy in October 1920, was discharged three years later and reenlisted in February 1926. Trained as a metalsmith, and later as a diver, he was commended in 1928 and 1930 for his excellent diving work. McDonald was designated a Master Diver in October 1934.
From May to September 1939, he was heavily involved in rescue and salvage efforts on the United States Ship Squalus.
Continuing his Naval service into World World War II, McDonald became a commissioned officer He retired after the war with the rank of Lieutenant.
James Harper McDonald died at the age of 73 and was buried in Fishing Creek Cemetery, Roulette, Pennsylvania.