Career
Born in 1839 in Boston, O'Brien was still living in that city when he joined the Navy. He served during the Civil War as a coxswain on the USS John Adams. On November 28, 1864, he was involved in the capture of the blockade runner Beatrice off Sullivan's Island in Charleston Harbor.
O'Brien commanded one of the launches which approached and boarded the ship despite heavy fire from the Confederate Fort Moultrie. Beatrice's equipment was then confiscated and the ship set afire. O'Brien's official Medal of Honor citation reads:
O'Brien was promoted to acting master's mate before leaving the Navy.
He died on October 1, 1894, at age 54 or 55 and was buried in Oak Hill Cemetery in Gloucester, Massachusetts.
