The Irishman has bagged 88 goals in 187 games since moving from Oldham in the 2014 January transfer window, though he felt his time at Pittodrie was coming to an end and jumped at the chance to join the National League side.
At the Peninsula Stadium he’ll work under former Scottish international Graham Alexander, while the owners of the Greater Manchester club include former United heroes Ryan Giggs, Paul Scholes, Nicky Butt, and Phil and Gary Neville.
Before leaving, Rooney said his goodbyes in an interview with Red TV.
He said: “I can’t thank the fans enough for what they’ve done.
“Not just at the games, but in and around the City and out where we are in Ellon, myself and the family have had a great relationship with them and it’s been brilliant.
“It’s a real family club. I think I’ve known everyone’s first name from my time over the years and it’s not as if there’s only four or five people working here.
“Everyone get’s on well, everyone’s pulling in the same direction whether it’s the football staff, the media team or catering staff, everyone at the club are really good people and it’s been great to get to know them.”
He added: “It wasn’t easy, but I just felt my time was coming to an end here and the opportunity came up at Salford.
“I spoke to my family about and I felt it would be a good opportunity for something new.
“I wasn’t keen to go somewhere else in Scotland and the move (to Salford) is something I’m really looking forward to taking part in and hopefully making a name for myself there.”