Charles Ellwood Colahan was born in Philadelphia, Pennsylvania, on October 25, 1849. He was appointed to the US Naval Academy, Annapolis, Maryland, from the Fourth District of his native state in 1865. Graduated on June 4, 1869, he was commissioned Ensign to date from January 22, 1870; Master, August 13, 1872; Lieutenant, July 20, 1875; Lieutenant Commander, June 19, 1897 and to Commander to date from July 1, 1900.
Following graduation from the Naval Academy in 1869, he was sent to European Station, where he had consecutive duty in the USS Juniata and the USS Franklin. In April 1872 he reported aboard the USS Portsmouth and later transferred to the USS Lancaster, both operating on South Atlantic Station. Ordered to Philadelphia, Pennsylvania, he was assigned in October 1875 to the Receiving Ship Potomac, continuing duty there from December 1876 to June 1877 in the Training Ship Constitution. He joined the USS Tennessee flagship of the Commander Asiatic Station. When that vessel was recalled for duty in the North Atlantic area, he was detached for service from March 1878 in the USS Monocracy.
Returning to the United States in December 1880, he was assigned until March 1883 to the League Island Navy Yard, Philadelphia, Pennsylvania, interspersed with instruction in torpedoes between May and August 1882. He had brief duty in the USS Tallapoosa before reporting in May 1883, aboard the USS Tennessee. During June and July 1886 he had special duty in New York, New York, after which he was attached to the US Naval Academy, Annapolis, Maryland. While there he participated in 1888 in the Midshipmen’s summer cruiser aboard the practice ship Constellation. He was a member of the Board, Navy Department, Washington, DC, from July 1889 to July 1890, when he joined the USS Philadelphia, and in June 1891 transferred to the USS Bennington, both operating with the North Atlantic Fleet.
In August 1893 he was again assigned to the Naval Academy, where he remained until July 1896. In 1895 he sailed with the Midshipman during their summer cruise in the practice ship Monongahela. Detached from the Naval Academy, he joined the USS Detroit. He was aboard the cruiser during the Spanish-American War and participated in blockade duty off Havana, Cuba, and in the bombardment of San Juan, Puerto Rico. Following the cessation of hostilities in August 1898, he transferred to the USS Chicago.
From April to June 1899 he was assigned to the Navy Yard, Boston, Massachusetts, after which he had in the Bureau of Navigation, Navy Department, Washington, DC On March 15, 1900 he became Commandant of Midshipmen at the US Naval Academy. While serving in that capacity he was in command of the USS Chesapeake (1900), USS Indiana (1901, 1902), during the Midshipmen’s summer cruises. He reported in May 1903 as Prospective Commanding Officer of the USS Cleveland, building at the Bath (Maine) Iron Works, but was detached on November 2, 1902, the day of her commissioning, and ordered to the Naval Hospital, Boston, Massachusetts, for treatment.
Commander Colahan had the Spanish Campaign Medal.