CBS announced it had launched an investigation into the allegations by six women who said Moonves sexually harassed them between the 1980s and late 2000s.
A bombshell article published in The New Yorker on Friday accused CBS chairman and chief executive, Leslie Moonves, of sexual misconduct stretching back decades and painted a broader picture of similar behavior within the most watched US television network.
The article makes Moonves, a distinguished executive who transformed CBS into a ratings winner, one of the most powerful American men implicated in the #MeToo era that ignited last year after the career implosion of Harvey Weinstein.
CBS announced that it had launched an investigation into the "recently reported" alleged misconduct. Reports about the story sent CBS shares tumbling more than six percent, hours before it was even published.
Six women who had professional dealings with Moonves told the magazine that he sexually harassed them between the 1980s and late 2000s.
Moonves, 68, joined CBS in 1995 from Warner Bros. Television, where his team developed hit shows such as Friends and ER.
Four described forcible touching or kissing during business meetings, and two said Moonves physically intimidated them or threatened to derail their careers, The New Yorker's Ronan Farrow reported.
"I recognise that there were times decades ago when I may have made some women uncomfortable by making advances. Those were mistakes, and I regret them immensely," Moonves said in a statement obtained.
"But I always understood and respected -- and abided by the principle -- that 'no' means 'no,' and I have never misused my position to harm or hinder anyone's career," he added.
The New Yorker said 30 current or former employees complained that such behavior extended from Moonves to other parts of the corporation, including CBS News and its flagship investigative program 60 Minutes.
But his wife, Julie Chen, whom he married in 2004 and who is the host of Big Brother on CBS, said she fully supported her husband.
"Leslie is a good man and a loving father, devoted husband and inspiring corporate leader. He has always been a kind, decent and moral human being," she said on Twitter.
Men at CBS News accused of sexual misconduct were promoted, even as the company paid settlements to women with complaints, The New Yorker also reported, suggesting a wider toxic environment at the network.
In a statement, CBS suggested the article did not accurately reflect a company that "does its best to treat its tens of thousands of employees with dignity and respect."
The corporation's board of directors had earlier issued a pre-emptive statement, saying that upon conclusion of its investigation, it would "promptly review the findings and take appropriate action."
In November, CBS News sacked Charlie Rose, at the time one of the most respected TV journalists in the United States, after eight women told The Washington Post he had made unwanted sexual advances.
Farrow shared a Pulitzer Prize with The New York Times for his reporting on Weinstein, which galvanised the #MeToo movement to quash pervasive sexual harassment in showbiz and other industries.
The son of actress Mia Farrow and film director Woody Allen said Friday his latest article was the product of an eight-month investigation.
In May, he uncovered allegations of physical assault that forced New York state prosecutor Eric Schneiderman to resign.
Farrow's latest expose raised speculation that Moonves might also be forced to step aside.
Nor was it clear what impact it would have on a legal battle for control of the US television giant -- between the Redstone family, which controls CBS, and the board, chaired by Moonves.
Shari Redstone is a major shareholder of both CBS and Viacom, and is seeking to merge the two companies. Moonves opposes the deal.
As chairman, Moonves oversees all operations of the company, which include the CBS Television Network, premium cable service Showtime, and the Simon & Schuster publishing company.
He has launched primetime CBS hits such as Everybody Loves Raymond, Survivor and CSI: Crime Scene Investigation.
He was promoted to president and CEO of CBS Television in 1998, and became chairman in 2003. A one-time actor, he is father to four children. Chen is his second wife.