Promoted lieutenant in 1839 and commander in 1855, he was commended for gallantry for activities at Tobasco during the Mexican War.
Injured while commanding the incomplete ironclad river gunboat Benton in 1861, Winslow was promoted captain the next year and took command of Kearsarge in April 1863. On 19 June 1864, Kearsarge sank confederate raider Alabama, for which Winslow was promoted commodore.
As rear admiral, he commanded the Pacific Squadron 1870–72. He died on 29 September 1873, soon after retiring from active duty.
He served two years at sea then required by law and was commissioned ensign on 18 July 1876. He subsequently served in Tennessee, Constitution, Tennessee again, Despatch, Pensacola, Kearsarge and Galena. Instruction at the Naval Torpedo Station and the Naval War College, Newport, Rhode Island, in 1887–1889, was followed by special duty in connection with Torpedo Boat N-1 from 23 December 1889 to 31 March 1890. He then placed Cushing (Torpedo Boat No. 1) into commission and continued in her command for three years.
On 29 March 1893, Lieutenant Winslow joined the USS Alliance, and when detached in January 1895, reported for equipment duty at the New York Navy Yard, Brooklyn. On 6 October 1896, he was detached from the New York Navy Yard with orders to the USS Terror, and in August 1897 was transferred to Nashville.
During the Spanish-American War, Winslow commanded a boat expedition from Nashville and Marblehead, which was sent to cut the cables off Cienfuegos, Cuba, which connected Cuba with Europe. In spite of extremely heavy fire at point blank range from the enemy on shore, a length of nearly 200 feet was cut out of each of two cables, by use of hacksaws. Lieutenant Winslow was wounded in the hand by a bullet, but retained command of the expedition. His superior officer reported: "The work performed by the people in the boats was both hazardous and difficult, and too much credit cannot be given to Lieutenant Winslow for his excellent judgment and consummate coolness, under most trying conditions of heavy sea and destructive fire of the enemy." He was advanced five numbers for extraordinary heroism during this operation.
On 10 October 1898, Winslow reported to the Indiana and nine months later was transferred to New York. From 16 December 1899 until 8 February 1900, he was assigned to the New York Navy Yard, and for fourteen months thereafter was in charge of the Branch Hydrographic Office at New York. He next served as Flag Lieutenant on the Staff of Commander North Atlantic Station, attached to the USS Kearsarge, flagship, and on 1 March 1902, reported to the Navy Department, Washington, DC, for a tour of duty in the Bureau of Navigation. While there he had additional duty as Aide to the President Roosevelt and with the General Board. On 19 August, he wrote a letter to the President, who ordered that a board be convened to consider the types and qualities of torpedo vessels and their machinery needed by the Navy, on which he served under Rear Admiral George A. Converse.
Winslow assisted in fitting out Mayflower, and from her commissioning on 12 July 1905, until 19 December that year, served on board. When detached, he assumed command of Charleston, and on 25 July 1907, returned to the Bureau of Navigation for duty as Assistant to the Chief of the Bureau. In March 1908 he was sent to New York in command of New Hampshire, then continued in command until 8 November 1909, when he became Supervisor of the Harbor of New York. He remained there two years.
Brief duty at the Naval War College, Newport, Rhode Island, in November and December 1911, was followed by command (in the rank of Rear Admiral) of the Second Division, Atlantic Fleet, his flag in Louisiana. He later commanded the Third Division, then the First Division (New Jersey and Florida respective flagships), and when detached from the later command on 1 January 1913, he returned to the Naval War College. There he remained until 23 April 1914, when he assumed command of Special Service Squadron, hoisting his flag in New York. That squadron, under his command, participated in operations at Vera Cruz in the Mexican Campaign during the period 4 May to 17 September 1914.
On 21 August 1915, Winslow was designated Commander in Chief, Pacific Fleet, and in the rank of Admiral hoisted his flag in the USS San Diego on 17 September 1915. He was so serving when relieved of all active duty and transferred to the Retired List of the US Navy, upon attaining the statutory retirement age on 29 July 1916. He was recalled to active duty during the early World War I period, and served from 18 September 1917, until 8 November 1919, as Inspector of Naval Districts on the Atlantic Coast, with the USS Aloha as flagship. He returned home on 11 November 1919.
Admiral Winslow died in Boston, Massachusetts, on 2 January 1932, survived by his wife, the former Theodora Havemayer of New York, New York, three sons and four daughters. Mrs. Winslow died at her home on Narragansett Avenue, Newport, Rhode Island, on 9 June 1945.
Source: Naval History & Heritage Command.