Martin O'Neill returned to management at Celtic FC in a dramatic mid-season appointment on 28 October 2025. O'Neill started his career in Northern Ireland, but spent most of his years as a player with Nottingham Forest, with whom he won the European Cup twice, in 1979 and 1980. He was capped sixty-four times for the Northern Ireland national football team, also captaining the side at the 1982 World Cup. His career as a manager encompassed teams including Norwich City, Leicester City, Celtic, Aston Villa and Sunderland. He guided Leicester City to the Football League Cup Final three times, winning twice. As Celtic manager between 2000 and 2005, he led that club to seven trophies including three Scottish Premier League titles and the 2003 UEFA Cup Final. After joining Aston Villa, he achieved three consecutive sixth-place finishes in the English Premier League and guided them to the 2010 Football League Cup Final. O'Neill became Republic of Ireland manager in 2013 and led them to qualification for the 2016 UEFA European Championship for the third time in the nation's history, beating the reigning world champions in the process.