Paul Dean could have collected more than half a million pounds on the bet, which he has now partially cashed out.
If he had decided to let the bet run on to odds-on favourite Envoi Allen in today's opening race, he could have been in with a chance of doubling his £250k win.
But, after a long night of deciding what is best to do, he took Betfair up on its offer of a payout before the Marsh Novices' Chase at 1.20pm.
Dean documented his journey on Twitter, with thousands rooting for him.
The offer means that if Envoi Allen wins, he will scoop £300,000, but if the 'banker' is defeated, he'll still get a tidy £250,000.
He said: "So after celebrations last night, 4 hours sleep, an hours walk at 5am I've decided to take a partial cash out offer of 300 Envoi / 250 the field.
"With other bets my position on the race is £322,000 Envoi or £250,000 the field."
The accumulator has consisted of 12-1, 10-1, 4-1 and 25-1 winners so far.
Betfair spokesman Barry Orr said: "At Paul's request we gave him a partial cash out offer which reflected his desire to have a portion of his bet still running on Envoi Allen, while also ensuring a substantial profit on his incredible bet.
"The offer sees Paul receive £250k if anything other than Envoi Allen wins the Marsh Novices' Chase today at 1.20 and an additional £50k should Envoi Allen win.
"Giving him a total of £300k and fulfilling his wish of being able to cheer home Envoi Allen with gusto."Featured Image Credit: PA