Gustavus Conyngham was born in County Dengal, Ireland 1744. He immigrated to the United States (Colonies) with his father a few years before the Revolutionary War and resided in Philadelphia, Pennsylvania.

His first naval command was the 100-ton cutter SURPRISE whose mission was attacking British shipping in the English Channel. After taking numerous prizes, he was given command of the cutter REVENGE which was larger and faster than SURPRISE. He continued to harass British shipping, taking more than 60 prizes in 18 months. Each ship captured was sent into a friendly port and the cargo disposed of in the interest of the revolutionary cause. Historians indicate that the proceeds from these prizes contributed materially to the operations of Benjamin Franklin and his American mission in France.

British influence finally forced the closure of French and Spanish ports to him, so he set sail for the West Indies where he convoyed American shipping in addition to continuing his task of capturing enemy merchant ships.

In 1779, Captain Conyngham returned to Philadelphia, but on his next cruise he was captured and taken prisoner as a privateer. He was interned first in New York and then in London, from where he escaped only to be recaptured while returning to America in 1780. Again, he escaped and was in France, preparing to cruise against the British, when the war ended.

Captain Conyngham returned to the merchant service and commanded the armed brig MARIA during the Quasi-War with France. Later, as a member of the common council of Philadelphia, he assisted in the defense of the city during the War of 1812. Captain Conyngham died on 27 March, 1819 and is buried in St. Peter's Churchyard in Philadelphia.