Townsend, who has 13 England caps, was fined in June 2013 by the Football Association and suspended for four months for breaching betting regulations and it proved a turning point in his career.
The Tottenham academy graduate explained how a mixture of an addictive personality and boredom saw him download a betting app during one of his nine loan spells away from Spurs and it soon spiralled out of control.
Townsend, 28, wrote on The Players’ Tribune: “I don’t drink. I don’t do drugs. I don’t think I’ve ever been inside a nightclub in my life. And yet I still managed to lose 46 grand with just one tap on my phone.
“I didn’t even have to leave my room. I’m probably the only lad in history to lose £46,000 lying in bed on a Wednesday night in Blackpool. This is not a golden boy story. Let’s make that clear straight away.
“You didn’t click on a fairytale, I’m sorry to tell you. I don’t like talking about myself too much, so I’m not telling this story for the whole world.
“I’m telling it for the people out there who have had their knocks -for those who have been misunderstood, depressed, lost, and especially the ones who have battled addiction.”
Townsend was 10 when his half-brother Kurtis died in a car crash and admitted “the pain has been with me my whole life” before he highlighted the roller coaster of emotions he had in the early part of his professional career.
After a failed loan spell with Ipswich, the Londoner returned to White Hart Lane and then made his debut for Spurs in January 2011.
He marked it with a goal and man-of-the-match display against Charlton in the FA Cup, but just over a week later was sent on loan again.
Townsend added: “I went on loan to five more clubs before I got back home to Spurs, and I think that’s where the trouble really started.
“I can remember exactly where I was when I had my first bet. I was bored in a random hotel room the night before a match, and I saw an ad on the telly for an app with a free bet.
“I downloaded the app and had a little bet to pass the time. Within a few months, I was out of control.
“I just kept losing. I kept trying to dig myself out of the hole. Then, in the blink of an eye, I’m completely addicted.”
Townsend revealed ahead of Birmingham facing Blackpool in the first leg of the Championship play-off semi-final during the 2011-12 campaign, he lost £46,000 on a single match.
“I remember when I was at Birmingham, it was the night before our play-off semi-final game. I was lying in bed, trying to get my rest,” he said.
“This was the biggest match of our season, and I couldn’t fall asleep. I kept checking my phone, placing more bets. That night, I lost £46,000 on a single match.”
After Townsend had hit “rock bottom”, he revealed he didn’t stop until he was caught by the FA.
But added: “I went to get counselling for my gambling addiction. And that not only saved my football career, it also probably saved me as a human being.”