James Harbord was born on 21 March 1866 in Bloomington, Illinois, United States. Harbord entered the military in 1889 at the age of 23 and was a soldier in the occupation force in Cuba following the Spanish-American War. From 1903 to 1909 he was the Assistant Chief of the Philippines Constabulary and again from 1910 to 1913, and in 1916 he joined the Mexican Border Service under General John J. Pershing. While under the command of General Pershing, he fought against Mexican units that crossed the border and later took part in the hunt for Pancho Villa, an expedition that met disaster.
After the United States entered World War I in 1917, Harbord became the chief-of-staff of General John J. Pershing and was promoted to Brigadier-General. During the Battle of Chateau-Thierry and the Battle of Belleau Wood, Harbord distinguished himself in the command of the US Marine Corps forces and won a Distinguished Service Medal and the rank of Major-General for his services in the war. In 1919 he was sent by President Woodrow Wilson to investigate the aftermath of the Armenian Genocide in the Harbord Commission, where he noted that the temptation for reprisals would make it hard for peace in the region to be achieved. From 1922 to 1947 he was the President of the Radio Commission of America, retiring shortly before his death at the age of 81.