Emigrating from his native Ireland, Connor volunteered for service in the United States. Navy and was assigned to the Union steam frigate United States Ship. His enlistment is credited to the state of Maryland. On January 15, 1865 the North Carolina Confederate stronghold of Fort Fisher was taken by a combined Union storming party of sailors, marines, and soldiers under the command of Admiral David Dixon Porter and General Alfred Terry.
He received the Medal of Honor for his actions during the Second Battle of Fort Fisher on January 15, 1865. Connor was one of nine crewmen from the United States Ship Minnesota who received the Medal of Honor for their actions during the battle. "The President of the United States of America, in the name of Congress, takes pleasure in presenting the Medal of Honor to Ordinary Seaman Thomas Connor, United States Navy, for extraordinary heroism in action while serving on board the United States.S. Minnesota, in action during the assault on Fort Fisher, North Carolina, 15 January 1865.
