[1] He served in the United States Marine Corps during World War II and was awarded the Bronze Star and a Purple Heart for his actions during the Battle of Iwo Jima.

As a representative, O'Dea worked on labor and penal reform bills and was a leader in the effort to redevelop the state court system.

[5][6] In July and August 1959, O'Dea was absent from the district attorney's office while he interviewed with law firms in the Western United States and established residency in Nevada in order to file for divorce there.

[9] McCormack appointed assistant attorney general William H. Sullivan to run the office on an interim basis.

[10] After leaving office, O'Dea went to work for Melvin Belli and applied to join the State Bar of California.