The 20-year old Generation adidas signee who was the Big East Defensive Player of the Year arrives at the Gillette Stadium after the Revs traded their fourth pick for the top selection with Toronto FC.
Revs head coach Jay Heaps was thrilled with the acquisition of Farrell who is expected to play immediately in 2013.
"We just felt that he was consensus No. 1 across [the board] from a lot of different feelings going into the draft," Heaps said.
"In college a lot of people were labelling him as the No. 1 pick when we were No. 4, but we still went to watch and see.
"He carried that pressure well, and I think those are important things. Then he also backed it up with a solid combine. When you're asked to perform at the level he's had to perform in the spotlight, I think that also shows a little bit of character."
Farrell added: "You never know until they call your name. I'm grateful for that. Obviously, there are a lot of top guys that are here. You just never know, so I'm excited for the opportunity to be in New England."