The highly-rated 18-year-old has penned a four-year deal on Wearside, and arrives for an initial fee of £8.1m, a sum that could rise as high as £12m if a number of performance-related targets are met.
Wickham became Ipswich's youngest ever player on his debut aged just 16 years and 11 days, going on to make a further 36 appearances for the Tractor Boys.
The 6ft 3ins forward has represented England at Under-16, Under-18, and Under-21 level, and was part of Stuart Pearce's squad at this summer's European Under-21 Championships.
After scoring nine goals for Ipswich Town last season, Wickham was named the Football League Young Player of the Year for 2010-2011.
Manager Steve Bruce said: "A number of top sides have been chasing Connor for some time now, so naturally we are absolutely delighted he has chosen to come to Sunderland.
"He's still very young but at 6ft 3ins he's a physical presence. With his height and style of play he'll offer us a threat in front of goal and complement our existing strikers.
"We have been watching him for a while now and he is improving and developing all the time. He's a great prospect and I'm sure our supporters will love watching him play."