His father, A. Bartlett Giamatti, was president of Yale University from 1978-1986, then president of the National League from 1986-89. In April 1989, he was named Commissioner of Baseball, but died five months later.
Appeared on Broadway in Chekhov's The Three Sisters and Eugene O'Neill's The Iceman Cometh.
Made his big-screen debut with a small part as the Kissing Man in 1992's Singles.
Provided the voice of Frank, Tiger Woods' talking club-head cover, in a series of popular Nike Golf commercials.
Breakthrough role was as radio exec Kenny "Pig Vomit" Rushton in Howard Stern's Private Parts (1997).