She was laid down as the MV Villanova on 22 May 1937 by Bath Iron Works, Bath, Maine, for F. J. O'Hara and Sons, Inc., Boston, Massachusetts. She was the last trawler built at Bath Iron Works for a United States owner). Launched on 21 October 1937, and delivered on 1 November 1937, she was acquired by the U.S. Navy on 6 August 1940. Villanova was renamed Bullfinch on 14 August 1940, and commissioned in ordinary, on 16 August 1940. She then commenced conversion to a minesweeper at the Norfolk Navy Yard, Portsmouth, Virginia. She was placed in full commission as USS Bullfinch (AM-66), on 22 October 1940. Her conversion was completed on 22 April 1941.