From the water, the private sea wall in Rom Reddy’s backyard looks like a concrete fortress guarding his mansion in Isle of Palms, S.C., a wealthy beachfront community east of Charleston. A sign on it reads: “No trespassing. Private property.”

Since 2023, he has been in a legal battle with South Carolina’s primary environmental agency and various other environmental organizations that say the wall is worsening erosion and breaking a longstanding law that has protected the state’s sapphire coastline, one of its major economic engines.

Now, instead of fighting the state, Mr. Reddy is hoping to run it.

The former Exxon and artificial turf executive has funneled his frustrations into a self-funded, long-shot campaign for South Carolina governor, pitching himself as a Trump-like outsider who seeks to dismantle a bureaucratic system that ruins lives. The wall, Mr. Reddy said, is a concrete example of his frustrations with what he calls “government overreach.”

But Mr. Reddy, facing a crowded Republican primary that has largely focused on affordability, is running a campaign partly inspired by a fight to fortify his mansion — worth roughly $9 million — at a time when Americans are feeling intense economic pressure.

The wall, he said, had made him “public enemy No. 1” to the state. It also ignited his political awakening.

“I was just minding my own business,” he said, “and then government comes after me — actually steps into my property — and says, That’s mine.”

In an interview, Mr. Reddy, who lives with his wife and their teenage daughter, said he was eager to shift the focus from his wall to his nascent campaign, which kicked off last month, much later than those of the other candidates.

Several front-runners have already emerged in the Republican primary, which has also centered around issues like tax cuts and poor infrastructure. They include Lt. Gov. Pamela Evette; Alan Wilson, the state attorney general; and Representative Nancy Mace. The primary is on June 9. Whoever wins is expected to also secure the governor’s mansion, as South Carolina is a deeply conservative state.

At a rally in Beaufort this month, Mr. Reddy broke down his résumé: an immigrant from India, raised by an Indian mother and Italian father; a political novice who wants to cut two-thirds of state agencies. He also founded a political action committee called DOGE SC, after Elon Musk’s Department of Government Efficiency.

“I don’t want to be elected, I actually — I don’t really care,” Mr. Reddy told the crowd, eliciting chuckles. But he was clear that he was serious about ending “the weaponization of government,” a phrase he deploys to describe unelected government workers and judges, including those who have gone after his sea wall.

Some in Isle of Palms say they loathe his blasé demeanor and sense of entitlement. Others said they supported the sea wall endeavor and wished they had one of their own.

But many were wary of speaking on the record because Mr. Reddy, who owns a local news outlet, has a litigious history. He recently filed a defamation lawsuit against a former mayor who was critical of his wall.

And the legal feud over the wall, if he is successful, could set a precedent for other beachfront property owners in the state to construct as they please on fragile shorelines in an era of accelerating climate change.

Mr. Reddy, who denies the fact that human activity is driving climate change, insists that the angry-rich-man portrayal of him is wrong. He invoked George Washington when discussing his wall, saying that the fight for “freedom and property rights go hand in hand.”

A bitter battle

Isle of Palms has become a destination for South Carolina’s nouveau riche, with gated, glass-covered pastel mansions often adorned with nautical flourishes like a dolphin fountain or symmetrical rows of palm trees. Some residents wish their community, a popular public beach spot, were more private. On a recent afternoon, a narrow trail to access the beach between two mansions on Ocean Boulevard was blocked by someone’s garbage bin.

In the summer of 2023, as the sea murmured behind his home, Mr. Reddy noticed that the artificial turf in his backyard was wrinkling. The sandy soil underneath was unstable, something that naturally occurs as active shorelines shift.

He paid someone to fix the issue with a six-foot retaining wall partially dug into the sand, parallel to the shoreline. A few months later, while Mr. Reddy was vacationing in Italy, a storm caused the wall to tilt, and he was concerned it would fall and hurt a person or a pet. (His neighbor’s curly Cavapoo, Levi, is known to prance around the beach.)

Mr. Reddy asked state officials if he could place sandbags near the structure. They said no, and they warned that the wall was illegal. Mr. Reddy was incensed. Directives from the state to take it down were ignored.

Around that time, he paid someone to fix the structure by attaching it to a proper sea wall about 100 feet long, the length of his property. Then the South Carolina Department of Environmental Services ordered him to remove the structures and fined him $289,000, one of the largest penalties of its kind in state history.

“They went nuts,” Mr. Reddy said. “Just crazy.”

His critics, though, believe the punishment fits the crime.

Put simply, environmental lawyers say, the Beachfront Management Act of 1988 prohibits private sea walls within South Carolina’s jurisdiction. Before the law was passed, people would place such structures in front of their homes to protect them, even though they had the opposite effect long-term by worsening erosion and threatening public beach access.

Such sea walls do not allow sand to naturally move landward, causing beaches to disappear and become swallowed by waves, said Rob Young, a professor of geology at Western Carolina University who researches coastal management. The waves also bend around the ends of the wall, he added, increasing erosion on neighboring properties.

Now, though, as more homes are threatened by rising sea levels, wealthy property owners appear more eager to push back on regulations. Some Republican state lawmakers have expressed a desire to loosen restrictions. If Mr. Reddy succeeds in his case, “it’ll be like Oprah Winfrey — everybody gets a wall,” Mr. Young said.

Amy Armstrong, executive director of the South Carolina Environmental Law Project, said it was ironic that Mr. Reddy was claiming government overreach, when it was he who was damaging public property.

“It’s one of the most egregious examples of a private individual believing that their rights are superior to the public’s rights,” Ms. Armstrong said.

Her colleague at the organization, Leslie Lenhardt, said legal alternatives exist for beachfront owners worried about erosion, like pumping in new sand to replenish beaches, or using sandbags during emergency storm conditions.

Other communities have struggled to combat private sea walls and other forms of “coastal armoring” that are intended to protect expensive property but end up worsening erosion. In Oahu, Hawaii, structures like sea walls are accelerating erosion on North Shore beaches. In Rhode Island, a country club is embroiled in a lawsuit over a sea wall it built in 2023.

In South Carolina, there is a long history of bipartisan political support for environmental protections. In the past, Gov. Henry McMaster, a term-limited Republican, has vetoed bills that have sought to loosen sea wall restrictions.

Mr. Reddy appears willing to fight his case for as long as it takes. He recently fired his lawyers, accusing them of being too expensive and too friendly with opposing counsel.

Last year, he defended himself in administrative law court in front of a seemingly bemused judge who watched as Mr. Reddy chided environmental officials sitting nearby.

“Your Honor, you stand between freedom and tyranny,” he said. “God bless.”

“Well, thank you for the blessed part,” Judge Ralph King Anderson III replied.

At the Beaufort rally this month at a Holiday Inn, many conservative voters had not heard of Mr. Reddy’s sea wall lawsuit, which has cost him around half a million dollars. Some had not even heard of him until his campaign ad came up on conservative radio.

Reviews from the few dozen in attendance were mostly positive. They liked that Mr. Reddy had no political experience and no intention of taking donations.

His campaign website has a chatbot function powered by artificial intelligence that has been tailored to answer questions about him.

When asked, “if Mr. Reddy is elected governor, will he make it easier for others to build sea walls in South Carolina,” the chatbot’s reply was swift: Yes.

“Rom Reddy’s core mission is to end weaponized government,” it said, “and return money and power to the citizen.”