Initially assigned to the sloop on the Asiatic Station, he returned to the United States with the outbreak of the Civil War and served in the gunboat during the Peninsular Campaign, March–July 1862; and, afterward, in the blockade of Charleston. In April 1863, he assumed duties as Executive Officer in the screw sloop and during attacks on Fort Wagner briefly commanded Marblehead. From August 23 to September 7, he commanded a battery of naval guns on Morris Island, and on the night of September 7–8, led the second division of a boat attack on Fort Sumter. The division made shore, but was smashed by gunfire. Remey and the surviving members of his party were forced to surrender. Following 13 months of imprisonment at Columbia, S.C., Remey was exchanged and returned to duty, serving in the sidewheel steamship until the end of the war.
