Simpson told Ipswich's website: "I really enjoyed my time at Sunderland last season. It was the first time I had played first-team football and helping them win promotion was great, hopefully I can do the same here. We're chasing the Play-Offs and my target is to get in the team and help Ipswich get into the Premier League.
"I've enjoyed my first week here and I'm looking forward to hopefully playing on Saturday at Portman Road.
"I asked Sir Alex Ferguson if I could go out on loan and he said that Ipswich had called about me.
"The boss said it would be a good move because Ipswich play good football and I jumped at the chance straight away.
"It was very important for me and United that I joined a club that has the same style of playing as at Old Trafford. United wouldn't want me to join a club that just knocks it long all the time so Ipswich are perfect for me."