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Nearly every morning since 1972, Jim Nakano has started his day at his Southern California doughnut shop with a cup of coffee and a fresh buttermilk doughnut.

The two in hand, he greets new and longtime customers as they wait in line picking between the nearly two dozen types of doughnuts The Donut Man sells. He then heads to the back of the shop to taste-test some of his stock, making sure everything is handled with care and fried to perfection.

“I don’t eat all the donuts,” Nakano told NBC News. “I eat part of it, look at it, and taste it. I look at the consistency.”

“Every time I eat a hot doughnut, I realize my wife was right: There’s nothing better than a hot doughnut with coffee,” he added.

The Donut Man is located on Route 66 in Glendora, California, and is open 24 hours a day, seven days a week, except for major holidays. Nakano calls it a “hole in the wall.”

“It’s more than that to us naturally,” he said. “But people spot it right away now so when they drive by they recognize it. The architecture is part of The Donut Man.”

“My wife says you should be glad that you make people happy and share donuts. I can never thank enough the kids, adults that come here."

The shop is particularly busy during the spring, Nakano said, when locals are willing to wait in half hour-long lines to taste the shop’s signature seasonal strawberry doughnut.

Over the past 45 years, Nakano’s shop has become a doughnut destination for those hoping to satisfy their late-night sugar cravings.

“We didn’t ever think we’d be big. At least I never thought it would grow very much, but I knew we could make a good living,” he said. “It was on Route 66, and we just liked the community and school area, so this is where we wanted to live and do business here.”

The Donut Man sells more than 20 different varieties of doughnuts, including tiger tails, cream cheese doughnuts, apple fritters, bear claws, pumpkin cream, old fashioned doughnuts, French cruller cream puffs, apple spice, red velvet, and other seasonal varieties.

One of the shop’s best sellers is the seasonal strawberry doughnut, made with fresh strawberries the shop gets nightly when the fruit is in season.

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“Our berries come from San Diego to Salinas, Watsonville area, depending on where they are picking,” Nakano said. “So we are lucky we get the very fresh thanks to my wholesale produce crop person.”

While the basic process of making a doughnut doesn’t change from store to store, Nakano said what sets his apart is how he and his staff handle the dough.

“Once you start, you only have so much time, and it depends on weather, humidity,” he said. “The other thing is to use the best oil and watch your temperature. ... You have to have pride in your work. If you don’t have that, it shows.”

Before opening The Donut Man, Nakano and his wife had considered hamburger and sandwich shops but were eventually drawn to doughnuts.

“We were just looking for a change in our life, to go on our own and try for the American Dream,” Nakano said. “She said, ‘I like hot donuts,’ and we looked at each other and said ‘OK, I’ll do the research on that’ and did that quite a bit.”

Nakano tried to learn as much as he could about the business and science behind the pastries before opening his shop. He visited French and Jewish bakeries and learned how to properly handle the dough and find the right consistency.

The name of his doughnut shop came about after visiting a restaurant with some friends. “A little girl came to our table and said, ‘Hi Mr. Donut Man.’ And right away everyone looked at each other and said, that’s it, that’s the name,” Nakano said.

But the famous strawberry doughnut didn’t happen right away. Nakano said that one year the surrounding area was filled with an abundance of strawberry crops.

“One of the grower friends came over to me and said, ‘Jim, you gotta start a strawberry donut,’” Nakano said. “So we looked into it and said we can do it, and we developed our own glaze and it just took off.”

And after strawberry donuts, came the popular peach donut.

“People love those strawberry donuts, and I said well if we do strawberries, we might as well do peach,” Nakano said.

Nakano was born in Boyle Heights in 1940 and was two years old when he and his family were sent to an incarceration camp in Poston, Arizona. Nakano’s neighbors offered to take the family in for a couple of weeks after they returned to California, Nakano said.

After his father completed his military commitment in Germany, the family moved to San Pedro, California, before settling in East Los Angeles and later, San Dimas and Glendora.

Nakano studied marketing at California State University, Los Angeles, and served in the U.S. Navy after graduating. He decided to open a doughnut shop in 1972 after working as a manager at JC Penney.

The doughnuts have garnered attention from locals and food critics and has even earned a mention on the TV game show “Jeopardy!,” where his Glendora shop was featured as part of a question.

One of Nakano’s most memorable moments running The Donut Man was when he received a call from the late Huell Howser, the host of “California’s Gold,” a popular travel TV series. Howser wanted to feature him on his show.

Shortly after the episode, the Donut Man had a line of cars all the way down the block, according to Nakano. “We were out of doughnuts the whole month,” he said. “ That’s how effective Huell Howser was in any restaurant.”

“Every time I eat a hot doughnut, I realize my wife was right: There’s nothing better than a hot doughnut with coffee.”

Pulitzer Prize-winning food critic Jonathan Gold has also interviewed Nakano. “He featured us in his ‘99 things to do before you die,’” Nakano said. “We can never thank him enough and lot of other food critics and writers.”

Nakano has always had a sweet spot for doughnuts. His first memory of them was as a young boy racing a cocker spaniel named Denny to a bakery truck. The dog would always win, and Nakano would buy it a doughnut before he got one himself. Now, Nakano said he’s thankful people are willing to wait in line for his doughnuts.

“My wife says you should be glad that you make people happy and share donuts,” he said. “I can never thank enough the kids, adults that come here. I meet so many people, and that’s why I’m still here."

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