The English player was also fined £40,000 costs after an independent tribunal found him guilty of match-fixing and spot-fixing in seven fixtures between 2008 and 2009, including one World Championship match. "It's totally outrageous that this has happened to me," said Lee.
"My kids are getting bullied at school. I have four young children and this is just wrong. It's been 11 months of this, it's just outrageous what I'm being put through. I've been angry for the last 11 months. Snooker is all I know, it's the game I know, a game I love. A 12-year ban is career over."
Lee, who has been serving a suspension from the World Professional Billiards and Snooker Association (WPBSA) since October 2012, fixed exact scores, first-frame results and overall outcomes of matches in which three groups connected to him bets in excess of £111,000, leading to winnings of £97,000.
"A dirty picture has been painted and I'm not happy about it," added Lee. "I've got to see my QC now and I'll issue a statement on this. I'll be playing snooker again."
Lee, 38, who was ranked eighth in the world at his time of suspension last year, has a right to appeal the decision that implicates him, his sponsor of the time, his then manager and his wife. He is expected to do that later this week.
Nigel Mawer, who heads up the WPBSA Disciplinary Committee Chairman, said it was a "sad" day for snooker, but insisted "cheats" had to be punished for their actions.
"It sends a very clear message that people who get involved in match-fixing are going to face very severe penalties," said Mawyer. "And in Stephen Lee's case it could possibly end his involvement in any snooker. We take no pride in that because it's obviously a very sad day for Stephen - and it's a sad day for the sport when we have a top player found guilty of match-fixing. But it's important we send a very clear message that match-fixing is not acceptable and we send a very clear message.
"A 12-year ban means it's highly unlikely that a player will come back and compete at the top level. Anyone to lose a match at such an iconic tournament like the World Championship is nothing short of shocking.
"I have sympathy for him. You have a player who was in debt, people in authority around him such as his manager and his main sponsor, who have caused him to do the wrong thing. But players must know what's right and what's wrong - and make the right decisions in these circumstances irrespective of the background, because the sport is more important than any other player.
"Stephen was a fantastic player and he'll be a loss to the sport, but we have to send a message to those who try and match-fix."
A statement from the WPBSA read: "The bets were placed by three groups of people. Lee was in contact with the groups in the lead-up to the matches in question and afterwards. In one case the person collected the successful bet and placed half of the winnings into Lee's wife's bank account."
WPBSA chairman Barry Hearn added: "You can never be 100% [clean] because people will always be tempted, but we monitor every single game and if there's anything untoward it comes to our attention.
As this case has shown, even if it's years afterwards, we will chase up and eliminate any corruption in snooker. That is our pledge."