O'Neill played 64 times for Northern Ireland and was team captain at the 1982 World Cup finals in Spain when they famously defeated the host nation. He scored eight goals for his country.
Martin was also a frequent visitor to the Milk Cup with Norwich City when he was manager at Carrow Road.
Born in Kilrea, which is close to Coleraine, O'Neill played for Irish League club Distillery and scored twice in their Irish Cup final win in 1971 before transferring across the Irish Sea to Nottingham Forest where he played under the legendary Brian Clough. He went on to play an integral role in Forest's golden era, in which they gained promotion to the top flight, won the League and League Cup in 1978, followed by further League Cup success a year later. He was dropped for Forest's first European Cup victory in 1979 after failing to fully recover from an injury, but he played in their 1980 victory. At club level he also played for Norwich, manchester City and Notts County.
O'Neill managed Wycombe Wanderers before Norwich City. He guided Leicester City to the League Cup final three times, in which he was twice victorious. In his time as Celtic manager between 2000 and 2005, he led the club to three Scottish Premier League titles and the 2003 UEFA Cup final in Seville.
After four years in charge, O'Neill resigned as manager of Aston Villa in August 2010.