O'Connell made his way into the Carlton side after playing underage football for the club. Although originally a centreman and ruck-rover, he was used as a defender when joined the seniors in 1970. He played most of his games in the back pocket and was a long kick of the ball. O'Connell was a member of Carlton's 1972 premiership team and also played in the side which lost the Grand Final the following season. In the 1973 decider he had been a replacement for the ill Barry Armstrong and was given the role of tagging Richmond star Ian Stewart.