Smalling will join United in July 2010 on a four-year contract for and undisclosed fee.
“My time at Fulham has been great and I have learned a lot about the game from Roy Hodgson and the coaching staff,” he told the club’s official website.
“But the chance of coming to the biggest club in the world is something I just couldn’t turn down. I’m excited about working with Sir Alex and the fantastic players in the squad.
“I’ve played a few times in the Europa League this year, but the thought of making the step up to the Champions League next year is great. I can’t wait.”
