Update 15.45pm: Newly announced Republic of Ireland manager Mick McCarthy said he jumped at the opportunity to take on the role.
"We will see won't we, whether this is a good decision or a bad one," he said.
"I was never, ever going to turn down the chance to come back and take the job. I have been asked by many Irish journalists in the past at my own club press conferences asking if I wanted to ever take the (Irish) job.
"My answer to that always is that if I was out of work and there was a possibility so taking up the job then of course I would love to be manager again. We will see that’s a good decision won't we in two years time but I’m looking forward to it, it’s great."
He added he is happy with the two-year cap on the job, but said his success with the team might extend that timeframe.
"I went to see John [Delaney] and Ruud [Doktor] and it was explained to me that the job was for two years and I'm happy with that. It is two years and trying to qualify for the European Championships.
"If we do really well and get to the final and win it, then there might be a push for me to stay. There might also be a job going in the Premier League and I might move on there. If we do badly and I don't qualify then you won’t hear from me anyway. It works for me.
"I would think that if I was taking the job for two years that yes, it was kind of vital that I qualify,
"As I’ve said before if I do and we do well then I can hand it over Stephen [Kenny] and that would be wonderful. If I don’t and we don’t do well, people might not be glad to see the back of me main in the way that I work or the atmosphere that I create.
"Ultimately, it is results that count. If we don’t qualify I guess I will be off then Stephen might be taking it on."
He added he will be reluctant to leave if he is a successful manager.
"I probably won’t," he said.
"Like I said, that’s two years down the line. Do you know the average tenure for a Championship Manager? 11 months. I’ve been given 24.
"Can I put this to you? What if Stephen Kenny comes in and rips it up with the U21’s and some club from England comes in for him? We don’t know what will happen in two years time.
"You are quite right, it might be that feeling (of staying on) if we’ve qualified for the Euros. If we do qualify then there will be something else for me. I might get a big job in China and retire on 10 million year or something like that."
Mr McCarthy said he is looking forward to working with the players.
"I am working with the national team, Terry Connor and Robbie Keane. I have been speaking to Ruud and he has been advising me that we have some good young players and Stephen, hopefully will bring some through from the U21's.
"I have from now until March to get the know the senior players and find out a lot of things about a lot of people as well as develop a relationship with Stephen [Kenny]. I hope I leave a good team and a good squad behind that can qualify for the next World Cup.
"Terry Connor has been with me since 2009.
"Taff, was previously here with me and was such a wonderful assistant of mine and saw me through my formative years to be honest with you.
"Robbie is a different one. I was asked would I consider him helping us out in some way, coaching or management role, just to be part of the setup and work with me. I gave it some thought.
"I couldn’t deny the idea of such young coach who’s got bright ideas and was one of our most capped players, our top goalscorer (getting involved). I think Robbie will have a real affinity with all the younger players coming through from Stephen and Ruud. He’s their hero.
"That’s going to be a real benefit to me. He will be driving up and down the country looking at players, having his backside in the car and getting sick of watching teams before reporting back to me and Terry Connor. That’s what he will be doing."
He said Robbie Keane suggested his role to McCarthy himself.
"It was [a role] suggested to me by Robbie," he said.
"First thing I thought was ‘you cheeky bollocks’ to be quite honest. But he is cheeky, he was cheeky and impudent as a player. I gave him his debut.
"There is more to [coaching] now but he always loved his football and was always serious about his football. Sometimes we used to clap him in training, some of the things that he did. Such a talent.
"He’s got his head screwed on in terms of wanting to become a coach in his own right. If we are talking about succession, whatever happens to me, in two years time then he should be part of that succession because he has a lot of offer."
Mr McCarthy said he generally takes on the manager role with teams that are struggling.
"Seldom have I ever gone, no never, to a team where they have been flying or doing particularly well,
"I took Wolves when they were relegated, Sunderland when they were about to be relegated. Generally, things need picking up for whatever reasons.
"We should remind ourselves that it is not that long ago that we [Ireland] qualified for the European Championships.
"Some players have retired, so it is the job at mine along with Stephen, Ruud, Terry and Robbie to find players without any friendlies beforehand, start in March and try and qualify. "
He added he has spoken to Declan Rice's father and he plans to speak to the player next month.
"I spoke to Declan’s father the other day and it was a good conversation.
"I would just like to clear up some misconceptions as well that Declan wasn’t at recent matches because he had a falling out with Roy or Martin. He has the upmost respect for both of those guys.
"But he was asked by Gareth Southgate to go up and see St. George’s Park and to see whether he could be enticed into playing with them [England]. There was a huge outcry that he shouldn’t play and then there were lots of different opinions.
"He didn’t say you wanted to or didn’t want to. But he found it overwhelming.
"I remember saying he should just get into the West Ham team, take a back seat and then see how he’s doing. He is doing well now and I’m going to go and speak to him in December when is father was around, sit down and have a chat with them both."
Mr McCarthy said he will try to to make Harry Arter "feel like he wants to play in the team".
"There has been enough press coverage on that (Harry Arter) subject and I don’t believe everything I read in the newspapers," he said.
"I will be speaking to everybody, all the players, I’ve got to. We don’t have any games so I’ve got to get around speak to all them and find out what their thoughts are.
"If Harry is feeling uncomfortable that I’ve got to try and alleviate that. I’ve got to make him feel comfortable, make him feel like he wants to play in the team.
He said he thinks he will be better as a manager this time as he is older and wiser.
"I’ve certainly lost some hair," he joked.
"I’ve gotten older, wiser, I think, and certainly have more perspective on life. I’ll try not to fall out with everybody as quickly as I did before.
"I’d like to think that the experience that I have gained since I was here the last time, I have won the league (Championship) twice and been in the Premier League for three or four seasons.
"Can I seriously tell you what I have learnt? No, I can’t really but I have learned some things that’s for sure."
"I’m certainly not a starry-eyed 36-year-old like last time (I was in charge) that’s for sure," he said.
"I was pretty much wet behind the ears. I’ve looked back and I’ve said to other people before how that was done and should have been at that age. I kind of adapted and we got to the play-offs and we ended up in the World Cup.
"So I had a modicum of success doing it. The job is still the job. I’ll get the players together, I will go and speak to them and work with them. We will endeavour to do our best and win games, do the best we possibly can for the players and the young players coming through.
"I’ve been managing in the Championship, getting players in and selling them on. I have been preoccupied with that for the last 16 years with Wolves, Sunderland and Ipswich Town. We’ve now got a good spell to go and find the players, see what we have got and decide what I want to do.
"You don’t get this job if the team has qualified. You don’t get this job if the team has not been relegated out of the Nations League. You always get it on a bit of a low. So the first job is to turn that around. I cannot do any turning around until March. I can be around doing stuff but ultimately I will be judged on results and how we play.
"I’m meeting Stephen Kenny tonight, he is playing dinner, apparently!"
He added that he does not believe he and Roy Keane should be remembered for the Saipan incident in 2002, adding he has huge respect for the Cork man.
"Why? What happened there?" he said when asked about the topic.
"Do you know, I honestly believe that both my career and Roy Keane’s career should not be determined by what happened there. We both had successful playing careers, he did far better than I.
"But I have gone on to have a pretty successful career as a manager. I’d rather be remembered for that and I think Roy would feel the same way. He should be remembered for the wonderful player that he was.
"The fact that when we got to Saipan, he had played such a big part in that, was instrumental [in getting us to the World Cup]. You know what, I have huge respect for him. So if people want to talk about it, good luck. I will not be answering any more questions on it."
He said he is aiming for Ireland's style of play to be like that of the 2002 team.
"Did you enjoy watching us in the Word Cup in 2002? I guess that is the style of play isn’t it?
"There are real misconceptions about styles of football. Seen a lot, heard a lot, read a lot and I much prefer winning football generally, especially with eight or ten games to play.
"Really, it is going to be about winning games. If we did that and we qualified or qualified for some play-offs then we could get players in, teams in, work with them and do different stuff.
"My view has always been to try and have an attacking game. I played 4-4-2 when I was here the last time. That won’t be happening I doubt very much because of the way football has been changing. Dominating the ball in midfield is probably one of the biggest things."
FAI Chief Executive John Delaney during a press conference at The Aviva Stadium. Photo: Niall Carson/PA Wire
FAI CEO John Delaney said Stephen Kenny was approached for the U21 job "quite a long while ago".
"We would’ve discussed with Stephen quite a long while ago about taking the U21 job and managing the underage teams," he said.
"It is something the Association wants. He has been an outstanding manager with Dundalk. He has been the most successful manager in the League of Ireland over the last number of years. It would’ve been something we wanted Stephen to do for quite a while.
"In discussions with Stephen, he has obviously made it very clear he wants to manage the (senior) ‘A’ job. He will get that opportunity in 2020 and is happy to do so.
"He will make that very clear tomorrow (in his press conference). The whole idea, as outlined today, is that Mick is in a project to get us to Euro 2020. Stephen is straight in managing the U21’s, managing the underage emerging teams as well. That is hugely important as a support to Ruud.
"Then after the Euros, Stephen takes the ‘A’ job. That is the plan, that is the strategy, that is the vision."
Ger McCarthy and Digital Desk
Update 3.25pm: John Delaney described Mick McCarthy's appointment as "a hugely positive day for Irish football" and thanked Martin O'Neill and his back room for their contribution over the past five years.
"It’s a hugely positive day for Irish football and we have a number of announcements to make," he said.
"Personally, I want to thank Martin O'Neill and his entire backroom team for their time in charge and five years they have given to Irish football. There have been great memories and that must be remembered.
"We reached the last sixteen of the Euros and the play-off against Denmark. There have been some great nights here at the Aviva against Germany, against Austria in Vienna."
Mr Delaney confirmed Mr McCarthy will be joined by assistant managers Terry Connor and Robbie Keane.
"I am delighted to announce on behalf of the FAI that Mick McCarthy is our new international manager. He will be joined by assistant managers Terry Connor and Robbie Keane.
"He is our second most successful manager ever next to Jack Charlton and achieved two play-offs in his time and into the last sixteen of the World Cup. We are delighted to have Mick McCarthy back as out international manager."
He also confirmed that Stephen Kenny will be Under 21 manager before taking over the senior team from Mr McCarthy after the Euros in 2020.
"Another announcement today is that Stephen Kenny will commence as our Under 21 manager and will be responsible for all underage teams and Ruud will expand on that later at a press conference tomorrow," he said.
After the Euros in 2020, Stephen Kenny will take charge of the senior international team.
Ger McCarthy and Digital Desk
Earlier: FAI confirm Mick McCarthy as Ireland boss; Stephen Kenny takes charge of U21s
Update: 2.55pm: The FAI has confirmed Mick McCarthy as the Republic of Ireland manager for two years.
They have also put Stephen Kenny in charge of the Under-21s with immediate effect, with Kenny succeeding McCarthy after Euro 2020.
Former Wolves manager Terry Connor will come in as assistant coach alongside former Ireland captain and record goalscorer Robbie Keane.
FAI Chief Executive John Delaney believes McCarthy has the skills and experience required to help Ireland fight for a place at EURO 2020.
Delaney said: "This is a very exciting time for Irish football as we are able to welcome back a proven manager at international level in Mick McCarthy and also look to the future with Stephen Kenny.
"Mick was a great player for Ireland and then had a terrific impact as manager by guiding the team to the Round of 16 in the 2002 World Cup following a memorable draw with eventual finalists Germany. There is no doubt that he knows international football and has the appetite to lead the team forward again.
"Qualifying for EURO 2020 is hugely important considering we are hosting four games at the Aviva Stadium and Mick will set about achieving that as soon as we discover our opponents in next Sunday's draw at Dublin's Convention Centre."
Stephen Kenny will be officially unveiled as Under-21 manager at a press conference tomorrow.
Earlier: Mick McCarthy expected to confirm intention to talk to Declan Rice at unveiling
Mick McCarthy is today expected to confirm his intention to speak with West Ham midfielder Declan Rice.
McCarthy will be officially unveiled as the next Republic of Ireland manager at a press conference at 3pm at the Aviva Stadium.
It is the second the time the former Irish captain will take charge, having departed in 2002 after a six-year spell.
McCarthy is believed to have signed a two-year contract with the FAI, while Stephen Kenny will leave his Dundalk post to take charge of the Irish under-21 team.
Rice has opted out of international football after England manager Gareth Southgate approached him about switching allegiances.
The 19-year-old has not been part of an Irish squad since winning the last of his three Irish caps in the friendly match against the USA last June.