The ex-England captain, who earned £300,000 a week at Manchester United, said he blew large sums after being “sucked in” by early betting success.
“I ended up chasing my bets trying to win my money back,” he revealed.
“You’re there to play for your country or club and when you’re losing money the way I was then it will affect you.”
Estimates of Rooney’s betting hell put his debt at £700,000 in five months from wagers on horses, dogs and football.
He reportedly lost £65,000 in two hours at a casino in 2008.
Rooney, 34, said: “I was a young lad who’d just come into a lot of money. For an away game with Manchester United you stay in a hotel – and with England you’re in a hotel for seven to 10 days.
“You get bored and do things to fill the time. At that time gambling was one of them. It was easy to place bets by phone. It didn’t feel like real money. Before you know it you’ve lost a good bit and you don’t realise the amount you’re putting on.”
“I won at the start and thought it was easy money. It sucks you in a bit more.”
“Thankfully I managed to pay up what I lost and I didn’t gamble again. I’ve learned from my mistakes. If you carry on gambling, you lose more. That’s when you can get sucked into a bad situation.”
He spoke in a video for online casino 32Red’s Stay in Control safer gambling scheme. The firm pays some of Rooney’s £90,000 salary at Derby County, where he has an 18-month player-coach contract.
Rooney will wear the No32 shirt for the club. His signing helped the Rams to secure a “record-breaking sponsorship deal” with the firm – but the tie-up has sparked criticism.
The Church of England’s gambling spokesman Dr. Alan Smith feels Rooney should refuse to wear the shirt to avoid influencing children. “Stars need to wake up to the fact they do fans no favours by wearing gambling logos,” he said.