The 22-year-old was a try-scorer in the Barbarians 52-26 win over Spain on Wednesday evening having been asked to tour Tunisia and Spain following an impressive performance for the famous club against the Army in April.
"I am delighted to sign a new contract," said Cornwell. "It has been a bit frustrating this season because I got a shoulder injury after starting the season with a run in the first-team.
"I now want to focus on getting a really good pre-season under my belt and be pushing for some game time next year."
Cornwell is a former captain of England U-21s and skipper of the Tigers Development side that reached the Guinness A League final for a third successive year.
He has made 17 starts for Tigers since his debut in October 2004, plus the same number as a replacement, and captained the first team in the EDF Energy Cup tie at Northampton this season.
Departing head coach Pat Howard said: "Matt has progressed well through the Academy here. He had a couple of a starts earlier in the season and we are delighted that he has signed a new contract."