Macheda has recently had loan spells at Sampdoria and Queens Park Rangers.
He told the club’s official website: “It’s great to be back at Manchester United. When you go on loan you really understand how important it is to play for this club.
“I’m really happy to be back and I can’t wait for the start of the season.
“Last season was disappointing. In the first six months I didn’t get a lot of opportunities here so we decided it was best for me to go on loan.
“When I got to QPR things went a bit wrong, though, as I was feeling my ankle a lot. But now I feel a lot better and want to start the season well. It’s a big season for me.”
Macheda admits he is looking forward to United’s pre-season tour to South Africa, China and Europe.
“I’m really looking forward to it,” he added.
“It’s always great to visit fans in different countries. You meet new people, you see new cities, you experience different cultures.
“I didn’t know how big the club was around the world when I went away for the first time in 2009. But I was very impressed by Malaysia, China and Korea.
“We have great support all over the world and I love being part of this team.”
