USS Andrew Doria was purchased by the Continental Congress in October of 1775. The ship was originally named the Defiance, but was renamed Andrew Doria, after being fitted out as a fighting vessel.

The brigantine was named after a 15th century Genoese admiral Andrea Doria. She was part of the first amphibious operation in the taking of Fort Montague as part of Esek Hopkins' fleet.

She was captained by Nicholas Biddle. After the taking of Fort Montague, she became the fleet's hospital ship after the other ships had an outbreak of smallpox. Andrew Doria was not affected as its crew had been innoculated.

The ship received the first ever salute by a foreign power when on November 16, 1776 she arrived at St. Eustatius. The Dutch island returned her 11 gun salute.