Martin O'Neill is one of the most passionate managers ever to grace the dugout. The experienced gaffer has been a big success nearly everywhere he's been, hoisting silverware with Celtic, Leicester, and Wycombe, while he was last seen at Nottingham Forest.
O'Neill is currently in charge of the Republic of Ireland, a position he has held since November 2013 - steering his troops through to Euro 2016 after beating Bosnia Herzegovina in the play-offs.
O'Neill's first managerial role was with Wycombe Wanderous back in the early 1990s. While at the club he won back-to-back promotions, taking them from the Conference to the Old Division Two.
In 1995 he joined Norwich City, who he played for briefly during his career, but only lasted six months after falling out with the Chairman. He then joined Leicester City with whom he won promotion to the Premier League and guided to two Football League Cups.
In 2000 O'Neill crossed the border to manager Celtic where he won three SPL, three Scottish Cups and a Scottish League Cup, as well as finishing runners up to Jose Mourinho's Porto in the 2003 UEFA Cup.
In 2006 O'Neill became manager of Aston Villa. Despite not winning any silverware with the club he made them a top 6 Premier League side as well as finishing runners-up to Manchester United in the 2010 Carling Cup Final. O'Neill took charge of Sunderland in December 2011 and led them to a 13th place finish.