The winger’s deal was due to expire at the end of the current season, but he has now committed his future to the Club for the following three campaigns.
Puncheon has been one of Southampton’s standout players in the Club’s first year back in the Barclays Premier League, making 26 appearances so far this season.
He has scored important goals in wins over Aston Villa, Queens Park Rangers, Reading and champions Manchester City, as well as a late leveller at Chelsea in January.
The 26-year-old has evidently grasped the opportunity to play top-flight football having had a limited role during his previous two seasons, when he spent time away from St Mary’s on loan.
Puncheon arrived at Southampton at the end of the January transfer window in 2010, and went on to be named in the PFA League 1 Team of the Year after an impressive start to life as a Saint.
But limited opportunities in the following season led to him moving on loan first to Championship side Millwall and then into the Premier League with Blackpool.
Despite Saints’ promotion to the second tier, Jason found himself on the move again, joining newly-promoted Premier League side QPR in September 2011 before returning to St Mary’s after Christmas.
Puncheon then battled his way back into First Team contention at his parent club, and the winger played his part in helping Southampton seal promotion to the top flight.
Having impressed during pre-season, Puncheon has featured in 23 of Saints’ league fixtures so far this season – a total bettered only by Rickie Lambert and Morgan Schneiderlin.
Puncheon’s performances have stepped up further since the appointment of new First Team Manager Mauricio Pochettino, and the wide-man was more than happy to commit his long-term future to the Club today.
“It feels amazing,” Puncheon said after putting pen-to-paper on his new contract.
“It’s obviously been a worry because my contract was up at the end of the season, so it was important for me to get tied down.
“It’s a weight off my mind, so now I can look to the long-term future. The Club has a vision, and that’s why I’ve signed and stayed on.
“We got to the Premier League in three years, and now the Club has a vision of playing European football – and we want to get there as soon as possible.
“I believe that can happen and, more importantly, the Football Club believes that can happen. They believe I can be a part of it and so do I.
“Now I want to finish the season strongly and keep growing as a player – and for us to keep growing as a football club.”
Manager Pochettino added: “It’s great news that Jason has agreed to sign a new contract with Southampton.
“He has been very impressive for the Club this season and especially so since I arrived, and he is a very important member of our squad.
“He has responded really well to the challenge of the Premier League and is clearly playing some of the best football of his career, so it’s really pleasing that he is staying here.
“Jason is a determined and passionate person, and that honesty and emotion has transferred into his performances and so he fully deserves this contract extension.
“I was never in any doubt that he would like to remain at Southampton, and I am looking forward to seeing even more from Jason over the next few years.”