In recent interviews, four women spoke on the record about a pattern of violent sexual behavior by Mr. Simmons, disclosing incidents from 1988 to 2014. Three of the women say that he raped them.

In each case, numerous friends and associates said they were told of the incidents at the time. The women said they were inspired to come forward in the aftermath of the accusations against Harvey Weinstein, as victims’ stories have been newly elevated and more often believed.

Told in detail about the rape accusations and other misconduct, Mr. Simmons, 60, said in a statement: “I vehemently deny all these allegations. These horrific accusations have shocked me to my core and all of my relations have been consensual.”

He added: “I have enormous respect for the women’s movement worldwide and their struggle for respect, dignity, equality and power.”

[Read Russell Simmons’s Complete Statement]

Last month, Mr. Simmons — a forefather of hip-hop who went on to great success in fashion, media and more — apologized for being “thoughtless and insensitive” and announced he was stepping down from his companies after the screenwriter Jenny Lumet became the second woman to publicly accuse him of sexual assault at the time.

“I have re-dedicated myself to spiritual learning, healing and working on behalf of the communities to which I have devoted my life,” he said in his statement on Wednesday. “I have accepted that I can and should get dirt on my sleeves if it means witnessing the birth of a new consciousness about women.

“What I will not accept is responsibility for what I have not done. I have conducted my life with a message of peace and love. Although I have been candid about how I have lived in books and interviews detailing my flaws, I will relentlessly fight against any untruthful character assassination that paints me as a man of violence.”

The most powerful men and companies in popular music have thus far gone largely unscathed in the national reckoning over sexual abuse. A major reason: Sex and debauchery are built into the music industry, where the boundaries between work and play blur in late nights at clubs and studios, and many women have scant power or incentive to complain about being mistreated.

These women still face powerful industry gatekeepers like Mr. Simmons, whose pedigree and ability to make or break careers allowed his abusive behavior to go unchallenged for decades, his accusers contend. “Russell was like the king of hip-hop,” Ms. Dixon said.

She said she was later harassed by another boss, L.A. Reid, the music legend known for his work with TLC and Mariah Carey, driving her from a business where women had little autonomy. In a statement to The New York Times, Mr. Reid did not address the specific claims but apologized if his words were “misinterpreted.”

Black women, especially, felt powerless against Mr. Simmons and his cohort in the small world of urban music, with several saying that misconduct against them could go unchecked because their place in the industry was so tenuous. They feared being ostracized, or worse.

Three of the women now accusing Mr. Simmons were pursuing careers in the music industry that they said were disrupted or derailed in part by their experiences with him.

“I didn’t sing for almost a year,” said Tina Baker, a performer who said Mr. Simmons raped her in the early ’90s, when he was her manager. “The second he agreed to work with me, my budget increased, the label was paying more attention to me,” Ms. Baker recalled. But after the assault, she said, “I went into oblivion.”

‘He Pushed Me on the Bed’

First known as a hyperactive party promoter turned manager from Queens who helped boost Run-DMC, Mr. Simmons was among the first to view hip-hop as a big business and cultural force. In 1983, with the producer Rick Rubin, he made Def Jam the defining rap label of its era, with hits by the Beastie Boys, LL Cool J and Public Enemy.

Even after Mr. Simmons sold his remaining stake in Def Jam for a reported $100 million in 1999, he served as an ambassador for hip-hop through comedy (“Def Comedy Jam”), clothing (Phat Farm) and activism. Today, his company Rush Communications oversees an array of businesses and nonprofits.

In 1987, Toni Sallie, a music journalist for the trade magazine Black Radio Exclusive, met Mr. Simmons while on assignment. She found him to be a charming, if gruff, playboy. They ended up going on a few dates before Ms. Sallie, then 28, decided they were not a match.