She was purchased by the Union Navy to be part of the fleet of ships stationed in coastal waterways to prevent blockade runners from entering or departing ports of the Confederacy.

Resolute, a wooden, screw tug built in 1860 at Keyport, New Jersey, was purchased by the Navy 7 May 1861 from A. Degroot of New York City; and commissioned 12 May 1861, Acting Master William Budd in command.

Resolute destroyed four boats 31 August 1861 inshore at Ferry Landing, Virginia; captured the schooner Jones 11 August 1862 and the sloop Capitola 8 November 1862; and during mid-July 1863, operated close inshore in company with USS Jacob Bell and USS Racer under fire of Confederate shore batteries at Mathias Point to protect unloading operations from the grounded Army transport George Peabody.

From August to October 1864, she acted as ship's tender to the coast defense monitor USS Roanoke (1855) anchored off Point Lookout, Maryland.

Subsequently under major overhaul 12 October 1864 to 11 January 1865 at Washington Navy Yard, Resolute returned to the Potomac Flotilla to resume cruising duty.