The winger, 18, puts pen to paper on a deal until summer 2016 a year to the day since he impressed Cherries manager Eddie Howe on trial at the club.
Despite the faith shown in his ability, Cornick, who has been an unused substitute on two occasions this season, doesn't expect to be breaking into the first team soon.
"There are a lot of strong wingers at the club so I am not expecting a miracle to happen and to be playing and starting any games," he told the Daily Echo.
"But if I keep improving and doing what I am doing, I could get on the bench again and just look forward to the development games."
Bournemouth sit 16th in the Championship after 16 games.