He grew up near Mount Holyoke College, in South Hadley, Massachusetts, where his father, Valentine Giamatti, was a professor of Romance languages and Italian literature. His mother, Mary Claybaugh Walton, was the daughter of Helen (Davidson) Walton and Bartlett Walton, who attended Andover and Harvard College. His paternal grandfather, Angelo Giammattei (so spelled) emigrated from Italy through Ellis Island about 1900.
A. Bartlett Giamatti attended Andover and Yale. He was pledged to Scroll & Key, and graduated magna cum laude in 1960, marrying Toni Smith that same year. Two of their three children, Marcus Giamatti, Paul Giamatti, and Elena Giamatti, have become actors. Bart stayed in New Haven to receive his doctorate in 1964. He became a professor of English at Yale University, an author, and master of Ezra Stiles College at Yale. He spent a brief period teaching at Princeton, but was at Yale for most of his teaching life. When his tenure as Stiles master ended in 1972, he was so popular that his students wanted to honor him with a present. Giamatti told them he wanted a joke gift and they got him a moosehead (from a yard sale), which was ceremoniously hung in the dining hall. As the new master took over, Giamatti told him in a serious tone, "I have only one solemn duty I have to convey to you. Take care of my moose."
He served as president of Yale University from 1977 to 1986.
His life-long interest in baseball came into play when he became President of the National League in 1986, and later Commissioner of Baseball in 1989. One of his main acts was the banishment for life of Pete Rose from baseball for betting on the sport and associating with known gamblers, detailed in the Dowd Report. He died, at a young age, of a heart attack weeks after banishing Rose.
Books: The Earthly Paradise and the Renaissance Epic (1966)