O'Keefe emigrated to the United States in 1848 and established himself in Savannah, Georgia. In 1871 he captained a ship to the South Pacific. After landing on Yap he became powerful by using tools from Hong Kong and East Asia to more easily create Rai stones; however, the ease of making the stone money ultimately helped lead to its decline during the period of German rule. Still the wealth allowed him to own an island, of which he was considered "king". Reportedly he had his own emblem, which showed the US flag waving over the letters "O K." He took two Yapese wives as well, despite already having a wife and daughter in Savannah.
In 1901 he died on the ship Santa Cruz returning to Savannah.
- O'Keefe's Island, where his home was located in Yap Harbor
- The New Book of Lists pgs 384–385