Sven Goran Eriksson says the offer from Notts County was "irresistible".
The Magpies have set a target of playing Championship football within five years before an assault on reaching the Premier League.
And Eriksson insists the challenge was irresistible.
He said: "It's great to come back to England, the weather is the same, as usual the press is the same, but I didn't expect anything else.
"I always said that I wanted to come back to the Premier League because it is the best league in the world - I chose a little bit of a difficult way to do it.
"It will take some years but I'm sure, talking to (executive chairman) Pete (Trembling) and the investors, we will do it.
"That's why I'm sitting here, I think it's maybe the biggest football challenge of my life to try to take, together with all the people, Notts County to the Premier League.
"That's the target and that's why I'm here - the challenge.
"It's maybe the most difficult football job I've had so far. But I'm looking forward to it and I'm very, very happy to be here."
Responding to suggestions he has taken the job for the money, he added: "I have signed a contract first of all, secondly, if it was for the money then I could have gone elsewhere easily for much, much, much more money.
"But I'm not here for the money, I'm here for the challenge."
Eriksson, who has penned a five-year deal and will live in Nottingham, has been joined by long-term assistant Tord Grip, who will take up the role of general advisor.