In a statement to fans overnight, the singer revealed he was quitting the band and would not be recording on their upcoming album.
Take That will continue as a trio with Gary Barlow, Howard Donald and Mark Owen.
Jason said: "I want to start by saying how proud I am of what we have achieved together over the years. However, at a band meeting last week I confirmed to Mark, Gary and Howard that I do not wish to commit to recording and promoting a new album."
Jason said he'd begun to question his future with the band after their 'The Progress Tour', which took place in 2011, and had decided it was the right time for him to step away from the group.
"At the start of this year and with my full knowledge and blessing the guys began writing new material. There have been no fallings out, only a decision on my part that I no longer wish to do this," he said.
"I know how much Mark, Gary and Howard enjoy writing and making music, and they know that they have my full support and encouragement to continue on with what is to be another chapter for the band."
The singer added: "I have spent some of the best years of my life with Take That and I'd like to thank everyone who has been a part of my journey, including my band mates, who I feel are like brothers to me. Most especially my gratitude goes to all of the good and kind, beautiful and ever-loyal fans of the band, without whom none of this could have been possible. Thank you."
The remaining members of Take That – Gary, Howard and Mark – said Jason's exit was a "huge loss both professionally and even more so personally" but they will continue with plans for their new album as a trio.
In a statement, they said: "We first became aware of Jason's reservations a couple of years ago but had hoped that by giving him the desired time and space he may begin to feel differently.
"This has not been the case and we now have to accept and fully respect his decision which we know hasn't been an easy one. Jason's energy and belief in what this band could achieve has made it what it is today, and we'll forever be grateful for his enthusiasm, dedication and inspiration over the years."
Jason is the second founding member of Take That to leave.
Fifth founding member, Robbie Williams, quit the band in 1996 and went on to have an enormously successful solo career. He temporarily rejoined the group in 2010.