His ornate casinos, which included the Bellagio, the Mirage, Treasure Island and Wynn, helped change the image of the Las Vegas Strip into one encapsulating glamour, fancy restaurants and exotic attractions like the lion-taming duo of Siegfried & Roy at the Mirage. The Bellagio, a huge hotel and casino on the strip, features an array of dancing water fountains that routinely fascinate tourists. Mr. Wynn eventually sold the Bellagio, along with the Mirage and Treasure Island.

Mr. Wynn made more than $28 million in total compensation from Wynn Resorts for 2016.

“The thing about Steve Wynn is this: He is the biggest name in the history of Nevada business,” said Jon Ralston, the editor of The Nevada Independent, who has reported on the state’s gaming industry for decades.

“People throw around the word ‘visionary’ all the time,” he said. “This guy really was a visionary.”

The allegations against Mr. Wynn are notable because he is one of the most prominent executives of a large public company to be hit with multiple claims of sexual misconduct. The claims could tarnish his company’s brand because his name is so closely identified with it. And given that casinos are a state-regulated industry, the allegations could have an impact on the company’s management of the casino resorts it operates and other projects under construction.

His planned casino near Boston came under scrutiny on Friday when the Massachusetts Gaming Commission said, “The suitability and integrity of our gaming licensees is of the utmost importance, and ensuring that suitability is an active and ongoing process.”

Democrats sought to capitalize on the revelations.

They pointed out that Mr. Wynn and the R.N.C.’s chairwoman, Ronna McDaniel, hosted a fund-raiser at Mr. Trump’s Mar-a-Lago club in Palm Beach, Fla., just last week to celebrate the one-year anniversary of his inauguration. Democrats noted that in the wake of The Times’s exposé on Mr. Weinstein’s decades-long pattern of sexual misconduct, Republicans had blasted Democrats for accepting donations from the Hollywood producer.

Representative Jacky Rosen of Nevada, a Democrat who is running for Senate, called on Dean Heller, a Republican senator from the state, to disavow support he had received from Mr. Wynn. She called the allegations “horrifying and disturbing.”