He graduated from the United States Military Academy ranked first in the Class of 1889, and served in the Army's Corps of Engineers.

[3] Winslow's father died in 1869 and he was raised by his mother in Washington, in addition to spending significant time at the home of his grandparents in Boston.

[6] In 1885, Winslow competed for an appointment to the United States Military Academy (West Point) offered by U.S. Representative Ambrose Ranney of Boston.

[2] His academic accomplishments were especially noteworthy because an extended period of convalescence after a horse riding accident during his senior year prevented him from regularly attending classroom lectures.

[9] From May 1896 to April 1898, Winslow served on the West Point faculty as assistant instructor of practical military engineering.

At the start of the Spanish–American War in April 1898, he joined Company E, Battalion of Engineers, which was assigned to the Fifth Army Corps for the Siege of Santiago.

[10] In October 1908, Winslow was assigned to Fort DeRussy, Hawaii, where he commanded harbor and river fortification construction on Oahu.

While in charge of the Military Section of the Office of the Chief of Engineers during the early period of the war, Colonel Winslow's services were marked by the energy, zeal, and good judgment which were essential to the procurement of personnel and equipment and the organization and training of engineer organizations for overseas service.General Orders: War Department, General Orders No.

[16] Mary Winslow Chapman (1903–1995) was a Raleigh author and real estate developer, and was involved in the historic preservation of her family's Goodwinslow mansion.