A retired Canterbury businessman who says he never wants to grow up has come forward as the mystery supermarket angel who recently helped out a Lincoln family.

Dean Graham, 56, son of late Mainfreight rich-lister Neil Graham, said buying people's groceries or paying for their restaurant bills was something he did on a weekly basis around New Zealand.

"It's just giving people something to put a smile on their face really," he said.

"These days it's a lot of doom and gloom, and things are tough for a lot of people."

Graham's charitable acts have hit headlines in the past, alongside a brush with the law.

Last year he won a Trade Me charity auction, paying $10,420 for a cardboard Lamborghini, only to sell it about five months later, donating the proceeds to I Am Hope.

Dean Graham often pays for people's restaurant bills and groceries. Photo / John Cosgrove

Then in November he won a Trade Me auction for a Martin Jetpack prototype, paying $158,200 for the single-person aircraft, which he intends in future to donate to Canterbury Museum.

In 2018, Graham was sentenced to 80 hours community work after admitting to charges of allowing his premises to be used for growing cannabis, a licensing breach under the Arms Act over firearms found at the property and possession of a cannabis pipe.

The father-of-five last month left more than $200 cash with a Lincoln New World checkout operator to pay for the groceries of the family who was behind him in the checkout queue.

Mother Jen Stewart told Star News she and her young family had just been through a difficult time as they recovered from Covid.

"I was just speechless," Stewart said.

"This person didn't know how grateful I was on that very week that he would pay for my shopping."

She used $100 to pay for her groceries and gave the remainder to a grateful single-mother friend for her groceries.

Graham said he first started random acts of kindness in supermarkets and restaurants about two years ago.

He was buying a sandwich at The Hub in Hornby when he saw an elderly couple behind him scraping up change for their lunch.

When he went back about two months later, one of the staff members told him the couple had started doing the same for others.

"I thought to myself: 'If I can do that and change the way people think, I think it's a good thing'," Graham said.

"I care, and I can help, I do want to change people's lives.

"I just think life is so short, I just want to put it out there to believe we all care for other human beings."

Among his most generous gifts was giving a friend a $100,000 Ford F-150 Raptor truck for his birthday.

"I said: 'Happy Birthday', and I threw him the keys - he just burst into tears."

He had also given away eight of his motorbikes to friends.

"There's no point dying with it."

Graham's cardboard Lamborghini. Photo / Supplied

He is not concerned some may take advantage of his generosity.

"Friends don't hang around me for that, because they know me from before when I had nothing," Graham said.

He said he started at the bottom of the ladder at Mainfreight, the trucking giant company which his father co-founded.

He was a storeman and rented with flatmates; when money was tight they would nick each other's drinks out of the fridge.

He had been married twice, been a solo father for eight years, and today lives with his partner on their Lincoln lifestyle block, where he is building a man cave.

Graham says he often pays for people's groceries. Photo / John Cosgrove

He said he had never made it a secret that he smoked cannabis, but hardly did it these days as he was getting "too old".

He did his community work at Rolleston Salvation Army, where he had been humbled by the good work of the charity.

He had gone back there on a yearly basis since, donating clothes.

He has had the opportunity to be a supermarket and restaurant mystery angel around New Zealand while buying motorbikes and cars and attending motorbike and car shows.

He loves to ride and collect motorcycles in particular, which includes two from the Easy Rider movie.

In addition, actor Keanu Reeves was to personally deliver one of a limited range of motorcycles the actor was building later this year.

When his man cave was completed, Graham would be bolting 25 motorcycles to the wall.

"I don't want to grow up, growing up is boring," he said.

- Susan Sandys, Star News