Charles K. Cummings was born in Massachusetts around 1870 and worked as an architect in Boston, Massachusetts, after his graduation from Harvard University in 1893. On April 4, 1917, he enlisted in the United States Navy Reserve, after which he trained at the Naval Training Station at Marblehead, Massachusetts. He joined the crew of the USS Mount Vernon as a lieutenant on September 27, 1918, and worked as the ship's communications officer until he was put on inactive duty on April 25, 1919. As the officer formally in charge of the ship's war diary, he composed a history of the ship's World War I service, which he presented to several crew members in 1921. After the war, he returned to his architectural career in Massachusetts. He and his wife, Lydia E. Cummings (born ca. 1877), had several children, including Francis, Charles K., Ethel, Evelyn, and Margaret. His brother, F. H. Cummings, served onboard the destroyer Dyer during the war.
The USS Mount Vernon , originally a ship in the North German Lloyd Line called Kronprinzessin Cecile , took refuge at Bar Harbor, Maine, after the outbreak of World War I. The United States government formally took possession of the ship in February 1917, and it was sent to Charleston Navy Yard to be refitted as a troop ship. Under the command of Captain Ashley H. Robertson and Captain Douglas E. Dismukes, the Mount Vernon transported troops between New York City and Brest, France, until the spring of 1919. On September 5, 1918, the ship was hit by a torpedo, which killed 35 crew members and wounded an additional 13, two of whom died in the following days.