The FlynnStoned Cannabis Company, a dispensary in Syracuse, N.Y., is the size of a large clothing store. Its wooden front doors have iron handles with finials in the shape of cannabis leaves. Inside, nuggets of cannabis flower, infused candies and vaporizers are laid out in glass cases spread over two stories. A lounge under a skylight on the third floor hosts concerts and yoga classes.

It is, by nearly any measure, one of the success stories of New York’s nascent legal marijuana industry. And the man behind FlynnStoned, a 43-year-old high school dropout and roofing entrepreneur named Michael Flynn, appears poised to build a weed empire, with FlynnStoned dispensaries from Brooklyn to Buffalo.

But Mr. Flynn’s hard-charging approach has drawn ire from communities where he is seeking to open more stores. And a recent deal-making spree, in which he has cut branding agreements with dispensaries all over the state to use his name, has drawn the attention of regulators, who are investigating whether he is violating the spirit, and perhaps the letter, of the state’s legalization law.

“They’re trying to stick a pitchfork in me,” Mr. Flynn said.

Mr. Flynn, who has tattoos on his fingers that spell “HIGH VIDA,” is in some ways the type of person whom the state’s legalization efforts were intended to support. His conviction for marijuana possession 25 years ago put him at the front of the line for a state license to sell recreational cannabis products, part of New York’s effort to right the wrongs of the war on drugs.

And in some ways, the success of his business is a bright spot in the state’s troubled marijuana rollout. As others struggled to get off the ground, hamstrung by a combination of complex rules and a slow bureaucracy, FlynnStoned made $30 million in revenue in its first year.

His ambitions have also encountered some familiar roadblocks. Would-be neighbors in New York City have sought to block new stores over concerns about crime and exposing children to marijuana.

At the same time, community boards and state regulators worry that his entrepreneurial attempt to sell the rights to the FlynnStoned name to about 30 dispensaries around the state amounts to preying on marijuana license holders who are less fortunate.

“It seems to not be in the spirit of giving the helping hand to those who were previously adversely impacted by anti-cannabis laws,” said Jesús Pérez, the district manager of a community board on Manhattan’s East Side, where Mr. Flynn is building a dispensary in what was the city’s last Hallmark store. “Just red flag after red flag seems to have come up about this that the community was not comfortable with.”

A Lifelong Calling

Mr. Flynn sees selling marijuana as his destiny.

“I just feel like I’ve been put on Earth to do this,” he said in a recent interview. “I’m just going to keep doing it as long as I’m having fun.”

He said he had started selling weed when he was 12, after his parents divorced and his father disappeared from his life. Left unsupervised, he got hooked on drugs. At 15, he moved out, bouncing among apartments and flop houses before dropping out of school. By the time he was 24, he was carrying hockey bags full of weed across the border from Canada, charging about $2,400 a pound in Syracuse, his hometown, and $4,000 a pound in Florida.

He was convicted of low-level marijuana possession when he was 18, paid a fine and avoided jail. Five years later, he quit drugs and took up roofing.

He started his first business, The Roofing Guys, in 2006. He set himself apart by offering customers financing and, as his main competitors fell to the wayside, he got rich.

“I was so addicted to drugs, alcohol and the party life,” he said. “I turned that around and got addicted to success.”

It has afforded him a different life with his wife, Angela, a high school classmate who gave him a Home Depot credit card in her name to help start the business. The couple have five children and live on a custom-built estate in the middle of a cornfield near Syracuse.

When New York legalized recreational cannabis in 2021, Mr. Flynn’s demonstrated ability to run a business and his marijuana conviction helped him win a license to open one of the state’s first legal dispensaries.

On Instagram, he shared video from the ribbon-cutting ceremony in June 2023 interspersed with photos of his lime-green Lamborghini Aventador and a diamond necklace bearing his store’s name encircling a green marijuana leaf. The video was set to a song called “Blow Up” by the rapper J. Cole, who sings, “This is a song for my haters/ Y’all got me feeling like the greatest.”

As FlynnStoned grew, so did the opportunities its founder began to see fanning out before him.

Building the Brand

Under New York’s legalization law, one shop owner is not allowed to control more than three dispensaries.

Mr. Flynn, regulators say, may have found a way to skirt that law.

In the wake of FlynnStoned’s success, other dispensary owners began reaching out to Mr. Flynn for help and advice, he said. Soon, he started to make deals with some of them.

Those deals allowed other dispensaries to use the FlynnStoned name in exchange for a small cut of their revenue, he said. Mr. Flynn added that he also connects the business owners with friends who are investors but “not Wall Street guys.”

“At first it was advice and help, and then it became, well, why don’t we just build the brand and help ourselves, too?” he said.

Mr. Flynn said the branding agreements do not make him an owner or investor. He declined to say how much revenue he takes, except that it was “not that much.”

But state officials have begun scrutinizing the deals, seeking to prevent big players from taking advantage of small, local business owners whom legalization was supposed to benefit. James Rogers, the director of a new unit within the Office of Cannabis Management that investigates potential ownership violations, said licensees were free to sign agreements that make their businesses work. But he said his team would unwind deals that give investors too much control.

“It’s the predatory behavior that we’re after,” he said.

The agency declined to say whether it was investigating Mr. Flynn, though Mr. Pérez, the community board official, said that was what he had been told by state officials. Mr. Flynn also said the agency was blocking some of the deals.

Robert Grannis, a 54-year-old farmer, got a license in 2022 and plans to open a FlynnStoned store in Binghamton. He said he had sought Mr. Flynn’s help after the state failed to provide the financing and real estate that it had promised to help early licensees open dispensaries.

Mr. Flynn initially offered to buy his license, Mr. Grannis said, but they settled on a branding deal, and Mr. Grannis took on an investor who paid for renovations. He declined to discuss the terms.

Mr. Grannis said the deal gave him peace of mind because he had heard horror stories of people building out their stores only for regulators to deny or delay their openings. Unlike liquor stores, cannabis licensees receive their final licenses only after their stores are built.

He said that what Mr. Flynn was doing in the cannabis industry was no different than what Starbucks did for coffee or McDonald’s did for hamburgers.

“We’re not doing anything but the American dream,” he said.

Axel Bernabe, a lawyer who helped to write the state’s legalization law and the rules for the market, helps Mr. Flynn structure the deals. Some industry insiders have criticized his involvement, but Mr. Bernabe said there is nothing wrong with what he or Mr. Flynn is doing.

“This idea that this is super shady is mudslinging business,” Mr. Bernabe said, adding, “It’s a play on building your brand, and everybody’s trying to do that.”

An Unexpected Turn

The deals had proceeded smoothly until Mr. Flynn began expanding in New York City, drawing vociferous backlash.

Residents protested his plan to put a dispensary in the former Hallmark store, near the United Nations. In Greenwich Village, where he is converting what had been an adult video store into a FlynnStoned, the community board dug up videos of him and others smoking at his Syracuse store, which is not allowed. A petition to stop him from opening another location in the Greenpoint Savings Bank building in Brooklyn also gained hundreds of signatures.

“I’m not anti-pot, but I am anti-dispensary,” said Tanya Arias, a Realtor who has lived around the corner from the Hallmark store site for 20 years. “It’s not a store that’s going to service the needs of our community.”

Mr. Flynn’s own words may cause him the most trouble. In September, he told the East Side community board that he was the sole owner of the forthcoming dispensary, that he had already signed a lease and that the Hallmark store’s owners had not paid their rent in months.

None of it was true.

He said he had not expected the opposition, but he bristled at questions that he felt were intrusive. “Whatever I said in that community board was just whatever I had to say to get the hell out of there,” he said.

Kuljot Bhasin, 63, who owned the Hallmark store with his wife, Amrita, sued Mr. Flynn for defamation. They are seeking at least $4 million in damages. Mr. Flynn’s defense lawyers said their client had not spoken maliciously.

“To come and disparage us to make himself look good to the board, that infuriated us,” Mr. Bhasin said in an interview.

Mr. Bhasin, a Sikh American immigrant, said he plans to reopen the business in a new location. But a part of him hopes that Mr. Flynn’s plans fall through, he said, so that he might be able to return to the shop where he sold cards and gifts for 22 years.

Alain Delaquérière contributed research.