The 21-year-old's existing deal had been due to expire at the end of the current season, but he has now put pen to paper on a four-year extension.
"I'm delighted that Connor has committed his future to us for the next few years," said head coach Gus Poyet. "After his contribution at the end of last year, he continued to improve his football and become an important part of our team.
"He keeps learning, he is able to adapt to different positions up front and he is enjoying our philosophy of play, so I'm really looking forward to keep working with him for the benefit of our club.
"I think it was very important to tie down a young English centre-forward as there are not many around, this shows clearly the way this football club wants to progress."
Wickham started his professional career at Ipswich Town before making a switch to the Stadium of Light for £8million in 2011.
Initial struggles to hold down a first-team berth led to loan spells at Sheffield Wednesday and Leeds United, but Wickham has since become a key figure in the Sunderland frontline.
After making eight Premier League starts in the second half of last season, Wickham has featured in all 15 of Sunderland's top-flight matches so far this term, often operating in a wide role.
Wickham took to Twitter following the announcement of his new deal, posting: "Glad to have signed a new deal at Sunderland. Thanks to everybody involved. #SAFC"
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