He was on football's scrapheap in 2006 after MK Dons boss Danny Wilson ditched him because of his attitude.
Wilson even warned other managers not to sign the winger, who was missing life in London.
Puncheon, 24, said: "I love the game but I wasn't always interested in the discipline of football.
"I was 18 and on my own in Milton Keynes - all I wanted to do was get back to London and do the things that my friends were doing.
"But the penny dropped when I was out of football for six months after I got released by the MK Dons.
"I deserved it - I was always right, I didn't listen to the manager and the coaches and I needed that shock.
"Danny Wilson told every manager what I was like and football is a very small community. He killed me."