In June 1897, Hughes was appointed a second lieutenant of Infantry and assigned to the 17th Infantry Regiment. In August he was assigned to the 4th Infantry Regiment and posted to Fort Sheridan, Illinois. During the Spanish–American War, Hughes served with the 4th Infantry in Cuba, and was wounded at the July 1, 1898 Battle of El Caney. After convalescent leave, he returned to duty at Fort Sheridan. Hughes received the Citation Star for heroism at El Caney. When the Army created the Silver Star in 1918, Hughes' award was converted to the new medal.