O'Leary was born in Portland and graduated from Yale University in 1969. He later attended Clare College, Cambridge University, on a Mellon fellowship and received a master's degree in 1971. He received a degree from Yale Law School in 1974. While studying at Yale Law, O'Leary acted as a coach for the Yale debate team. He then went on to a private law practice.
O'Leary married a fellow Yale student, Patricia Cepeda, the daughter of Colombian writer Álvaro Cepeda Samudio.[1] John and Patricia O'Leary had two daughters. The O'Learys endowed the John O'Leary and Patricia Cepeda Fellowship for the Study of Latin America at Yale College.
Political career
He served as a member of the Portland City Council 1975-82) and for a term as that city's largely ceremonial Mayor (1980–81). He ran unsuccessful candidate for the U.S. House from Maine's First Congressional District in 1982, losing in the Democratic primary.[2] O'Leary served as the United States Ambassador to Chile from 1998 to 2001.[3]