The Evening News revealed last week that the striker had agreed the deal and the Easter Road club have tonight confirmed that the 20-year-old has put pen to paper.
New Hibs head coach Neil Lennon made it one of his priorities to ensure Cummings remained at the club. He met the player in Paris ahead of a Euro 2016 match and convinced him that he should continue his development in the Capital before seeking a move elsewhere.
Cummings, who signed for Hibs in 2013, has been the club’s top scorer in each of the last two seasons.
He said: “I am delighted to have signed the new deal with Hibernian.
“There was never any doubt in my mind over where I wanted to be this season, and I’m relieved to get it over the line.
“I feel my game has developed a lot over the last few seasons, and I’m looking forward to continuing to progress under the new manager.
“Everyone is buzzing after the Scottish Cup win, from the players to the supporters, and I’m sure we can achieve more over the coming years.”