Michael Engfors, 61, had been sleeping rough for the last six years after losing his business and home following a divorce.
But his luck changed when he decided to spend $10 (£6) on the Eternal Splendour scratchcard from a petrol station in Aspen, Colorado, on Friday.
As soon as he scratched off the first number he realised he had won the $500,000 jackpot - which is equivalent to £332,000 - despite the odds of 840,000 to 1.
Michael, who has been battling alcoholism, initially kept the win to himself and spent one final weekend sleeping on the floor of a nearby church.
He has now revealed he would like to use the money to buy some skis and to try and reconnect with his daughter, who he hasn't seen for two decades.
Jeremy Kowalis, who works at the Aspen Homeless Shelter where Michael had been staying, told 9News: "Michael has seen a bottom that has pushed him right to the edge.
"But Michael never gave up.
"He knew that if he kept pushing on, eventually his luck would change."
He added: "I don't think he normally spends $10 a day on a lottery ticket.
"But he did that day, and it sure paid off."
Dr. Vince Savage, executive director of the shelter who took Michael to collect his winnings, told the Daily News: "It couldn't happen to a neater guy."