O’Connor (Thomas H.) is born in Boston.

The son of John and Mary (Meany) O’Connor, Thomas O’Connor attends Gate of Heaven School, graduates from Boston Latin School and Boston College, and receives a doctorate from Boston University. After serving in the U.S. Army in Southeast Asia in World War II, he marries Mary McDonald in 1949, settles in South Boston, and begins teaching at Boston College in 1950, and subsequently serves as chairman of the history department (1962-70). O’Connor’s first book in 1968* is followed by many others, and he comes to be called “The Dean of Boston Historians.” He dies in Milton on May 20, 2012, and is buried in St. Francis Xavier Cemetery in Weymouth.