كتب : Megan Detrie
"This is a football decision, a decision not driven by money," Carrick said on Tottenham's official website.
"It's an offer that has come at the right time for me both professionally and personally and I felt I couldn't turn it down."
The 25-year-old international was told by new boss Alex Ferguson that he will wear former captain Roy Keane's number 16 jersey.
Carrick heaped on the praise for former coach Martin Jol after signing the contract to Manchester United supposedly worth about 50,000 pounds per week.
"Martin is a great manager and has done an enormous amount for my career," Carrick said.
"Without any doubt he has helped develop me into a better player. He gave me a chance when I needed it, stood by me and I will always thank him for that.
"I've had a great time at Spurs and the Club has been brilliant for me."
The Spurs made an immense profit from Carrick, whom they signed from West Ham for £2.75m two years ago.
The initial fee provided by Manchester United is around 13 million pounds, with add-on available based Carrick's success at the club and on the international scene.
Though Carrick had two years left with Tottenham, he rejected a new contract offer in favor of Manchester United, something Jol doesn't hold against the player.
"I'm sure he will do well at Manchester United because he is very talented and we will miss having him around the Lodge," the Dutch coach said.