Son of a U. S. Navy Rear Admiral, Irvin van Gorder Gillis distinguished himself academically at the U.S. Naval Academy in 1894 and soon operationally while serving aboard his first U. S. Navy warships. Assigned to a torpedo boat in the Spanish-American War, he was hailed a hero for disarming a live torpedo while it was still floating in the sea. A talented naval engineer as well as leader of men, Gillis was rapidly selected to command a series of U.S. Navy warships, and eventually he was assigned as Assistant U. S. Naval Attache in Tokyo to observe the Russo-Japanese War.

Following more sea duty in the Atlantic he was sent to Peking as the first U. S. Naval Attacheto China, a job he held three times over the following 12 years. Following the second of these tours, and during his first period of retirement from the Navy in 1914, he was designated as chief intelligence officer for the Navy in China while simultaneously working for Bethlehem Steel Corporation and Electric Boat Company as their China representative to sell warships to the Chinese Navy. In 1917 he was recalled to active duty to China to replace the incumbent who was reassigned to command a destroyer in World War I.

Following the end of the war, Gillis was released from active duty and settled into his life as a civilian. Married to a Chinese princess, he remained in China from 1914 until his death in 1948, primarily collecting, sorting, cataloguing, binding and shipping tens of thousands of volumes of rare Chinese manuscripts that ultimately were to reside in Princeton University's East Asian Library.