The man said he completely forgot his lottery ticket until he noticed it again in his wallet while buying takeout with his wife.
"I can't believe I've been a millionaire for weeks without realizing," he said.
"Whenever I buy a ticket, I always hope to win a few hundred dollars, but this is insane. It took so long to sink in! It was a terrific night," he continued.
The man said the winnings will make his life easier.
"I want to help our family and friends and a few upgrades are needed around the house. There will be some investments and travel is certainly on the list. We're keen to do some nice weekends away this year," he said.
An unidentified man from Queanbeyan, Australia, won $5.5 million playing the Oz Lotto in March after he used the same numbers he had been using for 30 years.