The 61-year-old has been impressed by Keane's tactical awareness while the pair worked as television pundits on the Champions League.
Keane returned from the Ireland camp just days before the 2002 World Cup finals in Japan and South Korea after condemning the squad's preparations for the tournament and falling out with then boss Mick McCarthy.
And the 42-year-old recently found himself on the wrong end of a Sir Alex Ferguson broadside when the Scot's autobiography was published.
But O'Neill is adamant he has no qualms about working with the former Sunderland and Ipswich boss, starting with the friendly against Latvia next Friday.
O'Neill said: "I am absolutely delighted he is on board. He is an iconic figure, a great, great player, one of the best players to have played in the Premier League since its inception, a great, great player, so I haven't a problem with that there.
"He went into management - I see Sir Alex Ferguson's points there that he said that perhaps Roy might have gone into management too soon. I don't really know that.
"All I do know is that from working with him over the last couple of years, doing some television work on the Champions League games, I have found him very, very engaging.
"I have found his thirst for knowledge amazing. I see him at football matches when there's no need for him to be at games. He loves football.
"I think like all of us in the game, he has points to prove. I know how brilliant he was and I know how sometimes how polarised opinions can be with Roy, but I don't have a problem with that."