O'Neil earned a Bachelor of Science in Health and Physical Education from Penn State University in 1974.
Prior to coaching in the CFL, O'Neil spent three seasons as defensive coordinator for NFL Europe's Frankfurt Galaxy (2004–2006).
In 2010, O'Neil became an assistant coach for the Niagara-Wheatfield High School Falcons football team in Niagara County, New York.
Son Keith O'Neil played in the NFL for the Dallas Cowboys and the 2007 Super Bowl Champion Indianapolis Colts.
He played for the Indianapolis Colts and San Diego Chargers after setting several records for receiving at the University at Buffalo.