Culbert’s direct connection with the war began with his enrollment in the R.O.T.C., in which he rose, before the end of his senior year, to the rank of captain. Before that year ended, he left college to enter the U.S. Marine Corps training school at Quantico, Virginia. Here he received his commission as second lieutenant (M. C.), August 27, 1917, and was assigned to the 74th Company, 6th Regiment, Marines, stationed at Quantico. On September 17, he sailed with his regiment from Philadelphia for France on a vessel that was forced to put in at New York, whence its final departure overseas was made September 22. In this brief interval Culbert was married, September 19, to Miriam Edith Towle of Cranford, New Jersey (Wellesley, ’18), to whom he had been engaged for nearly a year.

Soon after reaching France, Culbert became so interested in aviation that he secured a transfer, October 16, to the First Corps Aviation Schools at Gondrecourt, where he was commissioned Student Naval Aviator, November 26. On February 5, 1918, he was assigned to Escadrille 217 of the French Army, operating in the Champagne sector. “For two months,” writes his friend and classmate, R.T. Fry, in the Triennial Report of the Class of 1917, “he flew with the French, but on April 1, 1918, was transferred back to the First Aero Squadron, then at Ourches in the Toul sector. During this time Culbert had become, as expressed by one of the majors of his former regiment, ‘one of our most skillful and daring aerial observers,’ a fact attested later by the award of the Croix de Guerre, made in recognition of his work during the battle of Seicheprey and other occasions.”

Lieutenant Culbert’s valour as an aviator continued. On 15 May 1918, while on a mission to photograph enemy Gaswerfer, Culbert secured aerial photographs when his pilot descended to 500 metres over the enemy second-line trenches under heavy anti-aircraft and machine-gun fire. Although their plane was severely damaged, they completed their mission and returned with the photographs. The crew both received the Silver Star citation.

On the evening of May 22, 1918, while flying near St. Mihiel Lieutenants Barneby and Culbert were hit by an anti-aircraft shell and crashed behind American lines. Barneby was killed instantly and Culbert died later that night.