It is Roy Keane
There is no other Irish person close. Who ever is second, is a distant second
He is the most influential sports person in Irish sporting History, and in British football history, and one of the most influential in World soccer history
19 major titles
An inspirational force of nature with the guile, skill and will to win at all costs, he almost demanded it, and he inspired his team to do it. One of a very select few Irish sports persons to excel in the heat of battle.
He literally dragged Man utd to their first Champions league win. Putting in an inspirational performance against Juventus in the the semi finals when they were looking at certain defeat against. Diego Maradona was left slack jawed at the dominance of the performance
This is a player that would have been the first pick on any team or country in the world.
This is a guy who played in the biggest and most competitive sport on the planet
His legend will live on for centuries