Howell beat American Peter Uihlein on the second hole of a sudden-death play-off in the Alfred Dunhill Links Championship at St Andrews on Sunday after the pair had finished tied on 23 under par.
The 38-year-old Englishman was ranked as high as ninth in the world in June 2006, shortly after winning the PGA Championship at Wentworth, but six years later was down in 367th after a number of injuries and loss of form.
“I have never played in an Open Championship here but to win a golf tournament as a professional at the Home of Golf is quite amazing and I am really thrilled,” said Howell, whose wife Emily is expecting twins in early December.
“It’s been a long, long road from the depths of despair. I have had a lot of support from people around me and this is as much for them as it is for me. The downs were pretty low and I lost my way in life and on the Tour as well.
“Off course I was not a happy camper and made some bad decisions around 2008 and took some time to sort through them. I owe Emily a debt of gratitude for having me back and showing me that we were always going to be a happy couple in the end.
“This is a sweet moment to be happy and settled with Emily and Freddie at home and the twins on the way, and to win a massive championship seals the deal. Hopefully it can spur me on to bigger and better things.”
Howell played in both of Europe’s record nine-point Ryder Cup wins in 2004 and 2006, the latter on the same team as Sweden’s Henrik Stenson, who underwent similar struggles before coming back to win the Tour Championship and FedEx Cup title earlier this month.
“I’m certainly aware of how Henrik has turned things around. He’s now better than ever and that’s what I’m working towards,” added Howell, whose win takes him top of the European Ryder Cup points list.
“Why can’t the next 10 years be the best of my career? I’d love to play in another Ryder Cup and you can’t get into teams without winning tournaments and playing in the big events. That’s what makes a victory like this so important.”
Uihlein (69) missed from 15 feet for a winning birdie on the final hole of regulation and then saw Howell — who shot a final round of 67 — hole from eight feet on the second extra hole to seal victory.
Shane Lowry finished one shot outside the play-off alongside England’s Tom Lewis.