"Michael is a world class forward with a proven goalscoring record at the highest level and that has never been in question," United head coach Alex Ferguson told the club's official website.
"Coming to Manchester United with the expectations that we have is something that Michael will relish."
Injury-prone hitman Owen, who was recently linked with lowly sides such as Hull City, left Newcastle United on Wednesday after his contract ran out.
Shortly after, United revealed their intention of bringing in the 29-year-old, and wrapped up the deal in no time.
Opportunity
From his side, Owen said that he didn't hesitate for a second to accept United's offer, saying he will do everything in his power to bring back his glorious days.
"I had just begun to talk to other clubs when out of the blue Sir Alex phoned me on Wednesday afternoon, invited me to have breakfast with him the next morning during which he told me that he wanted to sign me," he said
"I agreed without a moment's thought. This is a fantastic opportunity for me and I intend to seize it with both hands.
"I am now looking forward to being a Manchester United player and I am fortunate that I already know so many of the players here.
"I missed pre-season last year and am pleased that I will be starting at Carrington from day one.
"I want to thank Sir Alex for the faith he has shown in me and I give him my assurance that I will repay him with my goals and performances."
Knee Injuries
Ferguson has been seeking to bolster United's firepower since the departure of Cristiano Ronaldo and Carlos Tevez.
The Scots first looked to acquire the services of Karim Benzema from Lyon, but Real Madrid snapped up the France ace from under United's nose.
Later on, Ferguson's interest in Owen was unveiled.
The former England star was unlikely to be approached by any high-profile outfit, given that he had been struggling with multiple career-hampering knee injuries over the past years.
But medical examinations at Old Trafford indicated that his knee is no longer a concern.
Owen's move to the Red Devils will most probably infuriate Liverpool's fans, as the former England marksman spent the first eight years of his career at Anfield.
In 2004, the 89-time England cap joined Real, where he had a fruitless season-long spell before sealing a move to Newcastle.