He earned a Bachelor of Laws from the Gonzaga University School of Law and served as a captain in the United States Army during World War II.

After serving in the Army, O'Connell returned to Tacoma and established a private legal practice.

O'Connell was elected Attorney General of Washington in 1956, and served until 1969.

O'Connell was also the Democratic nominee in the 1968 Washington gubernatorial election, losing to Republican Daniel J.

[2] Soon after leaving office, O'Connell resumed his private legal practice.