A Sydney grandfather who unexpectedly won a $13.9 million luxury home is now selling the spectacular Sunshine Beach property, saying the move will help secure his family’s future.

The 80-year-old retired engineer took out the top prize in RSL Queensland’s Dream Home Art Union earlier this year, winning the Mediterranean-style mansion along with $250,000 in gold and more than $400,000 in designer furniture and luxury extras.

When he received the phone call telling him he had won, his family initially thought it must be a scam. He was at a pharmacy when the life-changing news came through.

“I have never won anything in my life – not even a meat tray,” the grandfather said.

“I’ve had to work hard for everything I’ve done.”

Now, only months later, the four-bedroom property, known as Maslina, has been listed for sale.

Selling agent Adam Watts told nine.com.au the winner was struck by the home itself, especially the quality of the craftsmanship throughout. Watts said the owner believed selling the property would do more for his children and grandchildren than holding onto it.

The three-level home sits just 50 metres from the beach and was designed and built by Sunshine Coast designer Paul Clout. It has been created with a resort-inspired, wellness-centred layout, including a gym, steam room, sauna, ice bath, plunge spa, wine cellar and several entertaining spaces with ocean views.

Watts said buyers inspecting the property had been drawn to its distinctive feel.

“It feels like your own private resort,” he told nine.com.au.

According to the agent, interest has come from local, interstate and overseas buyers. Some already knew the story behind the home before stepping inside, while others did not.

“One or two buyers had actually listened to the original winning phone call recording after googling the property,” he said.

After the win, the grandfather said he never imagined he would one day be told he owned a multimillion-dollar beachfront home. He also made clear that helping others mattered most to him.

“There are so many wonderful things I can do to help people with a win like this,” the owner said.

“That is what is important. I have done it all and I have got a nice life, but to be able to give to other people who are deserving is just a wonderful thing to be able to do.”

Dream Home Art Union raises funds for RSL Queensland, supporting Australian veterans and their families.