Career
O'Connor made his League of Ireland debut for on 4 March 1979. During his time at St Mel's Park he was twice top scorer in the League of Ireland in 1981/82 and 1984/85. He is also the all time leading scorer for Athlone.
He scored in the Parken Stadium in the first round of the 1981–82 European Cup. He scored his first goal for the Hoops on 17 November 1985 at Home Farm. He played no part of the 1986/87 season due to a broken leg.
He made one appearance in the European Cup in September 1987. In May 1995 he scored the decisive penalty to keep Athlone in the Premier Division. At the end of the 2012 League of Ireland season O'Connor is joint twenty seventh in the all-time League of Ireland goalscoring list with 117 league goals On 25 February 1981, O'Connor played for Republic of Ireland U21 at Anfield.
In May 1992 O'Connor was appointed player manager at. In the 1993/94 season he guided them to promotion. However they got relegated by penalties in 1996 with Michael retiring as a player and resigning as manager.
He was appointed manager again for a second spell for the 2006 season. His first game in charge was also the clubs first game at their new stadium in Lissywoollen but he resigned in July 2007.