Phil Neville told the Football Association (FA) that the chance to work as Inter Miami's manager was "too big an opportunity to turn down".
The former Manchester United defender left his role as head coach of England's women's national team on Monday to join the MLS club, after just less than three years in charge.
Neville was set to take charge of Great Britain's women's football team at this summer's Olympics in Tokyo too, a role he had expressed his desire for for many months.
But with his contract with the FA to have expired after that event, when current Netherlands boss Sarina Wiegman would then take over the Lionesses, he told his employers that a role with Inter Miami was something he couldn't refuse.
"I did have a fantastic job and I worked with absolutely fantastic people," Neville said during his first press conference as Miami boss on Friday, explaining his reasons for leaving his roles with England and Team GB.
"I've got to say, the players that I worked with were some of the best players I've worked with and I was sad to say goodbye to them a couple of weeks ago, but I think sometimes in your career you get opportunities that you can't turn down.
"When this opportunity came up, I sat down with my boss at the FA, Sue Campbell, and I said: ‘Look, I've got six months left on my contract. Yes, we've got an Olympics, but this is just too big an opportunity for me to turn down'.
"It's something that I had always aspired to [do], to work in America, but to work for a great football club. Sue didn't stand in my way. I've got to say a massive thank you to Sue for allowing me to follow my dream.
"I’m sad to leave such a great organisation, who will continue to do well. They've got a coach coming in, in Sarina, who will do a fantastic job and hopefully they will go on and get that gold medal that we've all strived for for the last 10-15 years.
"But, ultimately, I think in life you get one opportunity and I think this was my big one opportunity that I had to grasp and I did it with the help of everybody else. I'm really looking forward to the challenge ahead."
Neville's role with Inter Miami will be his first as a leading coach in the men's game, with him having assumed roles as an assistant at Valencia and as youth coaches with both England and Manchester United in the past.
But despite that, he believes he has plenty of experience to take on his next challenge.
"I've got a lot of experience - a lot of experience of being around winners, a lot of experience about winning myself as a player, but actually coaching at the very top level in Spain with Valencia, at Manchester United and with the England national team, getting to a World Cup semi-final," he said.
"In terms of what we want to build here, we've talked about identity, we've talked about connecting with the public.
"We have to behave in a certain way and I call it elite behaviour. Elite behaviour is doing the right thing, every minute of every single day.
"I've lived that myself as a player and I've seen and coached that way, with some of the best players in both the men's and the women's game.
"I'm coming into this job to instil those values into this football club, about what it takes to actually win. I think I know those qualities and what it takes."
