The Boys in Green boss praised his assistant manager's positive attitude suggesting that his presence will be "fantastic for the nation"
O'Neill appointed Keane as his assistant when he agreed to succeed Giovanni Trapattoni as Ireland boss at the beginning of November and revealed that the 42-year-old "jumped at the chance."
"I just want to say something about [Keane], when I mentioned to him if he fancied it, he jumped at the chance," O'Neill told reporters. "He jumped at it immediately and said: 'Let's go and do it, it will be great.'"
The former Celtic and Aston Villa manager started his tenure as Ireland boss with a victory and a draw against Latvia and Poland respectively and he praised the "excellent" impact that Keane had on the players.
"I personally think he'll be fantastic for the nation," added O'Neill. "He's already made a great impression on the players themselves, who I think secretly might have been a little bit concerned but he's been really excellent.
"He wants to do it. He has enthusiasm which is always there and is there in abundance. If enthusiasm alone was to get us through that would be great but unfortunately we need a bit of luck along the way. We've got some decent players as well."
O'Neill also indicated his desire to be successful and paid tribute to his predecessor Giovanni Trapattoni, describing the Italian tactician as a "fantastic manager."
"It would be great to be successful with the Republic of Ireland, following in the footsteps of an absolute fantastic manager in Giovanni Trapattoni."