The 19-year-old Canadian, who follows on from his father who played for Newcastle in 1976, said he would be happy to play in the lower leagues to gain experience.
The youngster, who some would argue has shown more passion in the side that a few of the experienced internationals this season, scored his first senior goal for the club in a 2-2 draw with Manchester United on New Year's Day.
Toon Youngster Gets New Deal
Edgar: "I am delighted to have signed the contract and to have my future at Newcastle United.
"I guess I will always remember scoring against Manchester United as the highlight of the season.
"Now I aim to work hard and push for more chances in the first team next season."