The 19-year-old defender today joined fellow Leith youth-team recruits David Gold, Paul Grant, Dean Horribine and Euan Smith in agreeing new one-year contracts.
Centre-back Forster made his first-team debut in the Edinburgh derby win at Hearts last month and deputised for injured skipper James McPake in the 3-0 Scottish Cup final defeat to Celtic.
He said: "The past couple of months has been absolutely unbelievable for me and I can't wait to kick on and progress even further next season.
"It just goes to show that if you work hard then you do get your rewards - I went from being a long way from a first-team start to playing in an Edinburgh derby and a Scottish Cup final.
"I love playing for Hibs and I'm looking forward to helping the team to win matches next season."
Midfielder Gold, 20, has captained the Under-20 team for the past two seasons while Horribine, 20, made his first-team debut in the penultimate game of the Scottish Premier League season when he came on as a substitute at Kilmarnock.
Horribine said: "I'm delighted to be at Hibs for another year. Hopefully I can kick on and become a first team player next season."