John E. McMahon

Major General John Eugene McMahon (December 8, 1860 – January 28, 1920) was a United States Army officer who served in numerous conflicts, most notably in World War I, where he commanded the 5th Division. He also was the father of John E. McMahon Jr. (1890–1971), a career Army officer who attained the rank of brigadier general.

Early life McMahon was born on December 8, 1860, in Buffalo, New York, to Colonel John E. McMahon and Esther Bryan McMahon. He graduated from Fordham University in 1880 with an A.B. degree, and he entered the United States Military Academy (USMA) at West Point, New York, and graduated number eleven of seventy-seven in the class of 1886. Several of his classmates included men who would, like McMahon himself, eventually rise to general officer rank, such as John J. Pershing, Charles T. Menoher, Walter Henry Gordon, Edward Mann Lewis, Mason Patrick, Julius Penn, Avery D. Andrews, George B. Duncan, Ernest Hinds, William H. Hay, James McRae, Lucien Grant Berry and Jesse McI. Carter.

Early military career McMahon was commissioned in the Fourth Artillery, Artillery Corps. From 1891 to 1895, he was an aide to General Alexander McDowell McCook. During the Spanish–American War, he was the adjutant general of Second Brigade, Provisional Division, from June to July 1898. He was in Puerto Rico in 1898 and 1899, and served during the Philippine–American War.

He served in the Spanish-American War and was promoted again, this time to captain, in May 1898, and was also made an assistant adjutant general. That same year saw him graduate from the Artillery School. In July 1899 he became a major in the 31st Infantry and, following the end of the Philippine–American War which he briefly participated in, McMahon was mustered out in June 1901, after having been made a captain of Artillery in January of that year.

In January 1907 he was promoted to a major of Artillery before being assigned to the newly created Field Artillery Branch. While serving on the General Staff from 1911 to 1914 he was promoted to lieutenant colonel in May 1911, before being made a colonel several years later, in June 1916, by which time World War I had been raging for almost two years.

World War I Major General McMahon (center), commander of the 5th Division, and members of his staff in France, October 15, 1918. Stood to the left of McMahon is his chief of staff, Colonel Clement A. Trott.

In late August 1917, almost five months after the American entry into World War I, McMahon was promoted to the temporary rank of brigadier general and was assigned to command the 160th Field Artillery Brigade, part of the 85th Division.