Injury there halted his ascent and a second spell with Stags failed to rekindle the flame, but as he looks for a new club following his recent release from Grimsby Town, he told Mark Plumb in a fascinating interview of why he left Stags after promotion.
“Though I don't regret anything about my career, when I look back on it now, the way that Mansfield played that season when we went into League Two, if I had stayed I think we would have got promoted again with the players that we had,” he admitted.
“But, as you do when you're hot and scoring goals, you get a lot of different voices from a lot of different people in my head.
“I had an opportunity to better myself and play for a Championship club.
“The chairman made me an offer that probably wouldn't exist in football these days. But I had to turn it down to go and play in the Championship.
“That was what I really wanted to do. My dream was to go to the Championship and you never know, you could go to the Premiership.
“I went to Birmingham training for a week, which was probably a mistake as it devalued me a bit as it made other clubs hold off to see what Birmingham's opinion was of me.
“But I trained really well, playing with some big names and enjoyed the luxuries you get at that level.”
He continued: “They offered me a good contract and wanted my family to move down to Birmingham. They gave me an opportunity and I went with my ambition.
“Looking back on it, and the chairman did say this to me and Coxy (manager Paul Cox) too, one more season at Mansfield and you will go higher again.
“They said if you go and do what you've done here one more season you will go up again and it will be more lucrative for everyone.
“But agents, mentors and different people in your ear, it's a lot to handle as a young man and a big decision to make.”
Stags have just signed Green's ex-Grimsby team mate Elliott Hewitt and he said: “I would say you're in for a treat with Elliott as he really is a Rolls Royce.
“He has got great composure on the ball, he is very competitive, and he is absolutely rapid as well – deceivingly. He is a great pro and lives right.”
Green, 34, is now waiting for his phone to ring with an offer.
“I am looking for a new club. I am speaking to a couple of people but there's nothing set in stone yet,” he said.
“We have got another month or so until the season starts. All I can do is keep myself fit and ready.
“The transfer market has been slightly slow with Covid, though maybe not for Mansfield as I know they have made some very good signings.
“As a striker you're sometimes last on the list as defenders and midfielders come first as managers want to build from the back and build a good core first.”
Green now takes being released much better and is ambitious to help young strikers after his career is over.
“I understand football now and you can't take these things too personally. You have really got to be thick skinned in that respect,” he said.
“As I have got older I have mellowed out. How, whoever is playing in my position I want them to do well and score goals.
“As much as I hope that I have got two or three years left in the legs, I hope that with the skills I have learned I can show young strikers coming through.”