But since spells with Aston Villa and Sunderland, will he ever get a big job again?
He was sacked on Easter Saturday, and there has been a rise in young managers at the top clubs including the likes of Pep Guardiola, Jurgen Klopp and Jose Mourinho.
At the age of 61, having just been given the boot from the club he wanted to manage the most, will he get a chance to manage at the very top?
There’ll be no shortage of takers for him, but clubs struggling, and for him it will be starting from scratch.
It is probably unfair to say that O’Neill is on a downfall. It’s a blotch on the CV certainly, but let's hope Sunderland was not the final nail in his coffin.