The married father-of-one from Aberdeenshire started by betting just 20p per spin in the Hall of Gods casino BetVictor site while his winnings grew into a multimillion-pound pot.
Delighted, the winner who has not been named, said: "There's no need to ask how I'm feeling, yahoooo should answer that.
"When I won, the first person I told was my wife. She was as shocked as I was. I can only compare the feeling of winning as equal, but different, from the day I saw my son born."
"I guess we all chase the dream and winning the biggest ever UK online jackpot has been a dream come true for me and my family as it will change our lives - we have no worries about the future now."
The fisherman had previously played the sportsbook and poker games on BetVictor and was tempted by the big jackpots to play the casino slots, but never thought he could win such a big amount.
He will take time to decide what he will do with the money but will give some to charity and will continue to work as a fisherman because otherwise he'd miss it too much.
Andrew Dymock, head of eGaming at BetVictor said: "I couldn't be happier for one of our most loyal of Scottish customers to pick up this fantastic jackpot and it was a pleasure to congratulate him after his win.
"This jackpot is the biggest single win BetVictor has ever paid out and we are delighted to say that we've paid out £10 million to two lucky BetVictor players in the last six months."