NEW YORK — Matt Lauer’s firing for what NBC said was “inappropriate sexual behavior” with a colleague stunned viewers Wednesday, rocked the network.

The “Today” show host has long been one of the most-liked and highest-paid figures in the TV news industry.

Network news chief Andrew Lack said in a memo to the staff that NBC received a complaint about Lauer’s behavior on Monday and determined it violated company standards. NBC said the misconduct started when Lauer and a network employee were at the Sochi Olympics in 2014 and continued beyond that assignment.

Lack said it was the first complaint ever lodged against Lauer, but “we were also presented with reason to believe this may not have been an isolated incident.”

Lauer becomes the second morning host in a week to lose his job over sexual misconduct allegations. CBS fired Charlie Rose after several women who worked for him complained about his behavior.

Messages to Lauer and his agent were not immediately returned, and the network would not say whether he denied or admitted to any wrongdoing. He is married with three children.

Lauer, 59, has essentially been the king of television morning news since first being paired with Katie Couric on “Today” in 1997.

For many years, “Today” was the unquestioned ratings leader, until it was eclipsed by ABC’s “Good Morning America” following the ugly 2012 firing of Lauer’s co-host Ann Curry. The show had stabilized in recent years with Lauer’s pairing with Savannah Guthrie.

Lauer’s “Where in the world is Matt Lauer?” segments were popular for years, and he was used by NBC for other events. He had been scheduled to host the network’s coverage of the Rockefeller Center Christmas tree lighting ceremony Wednesday evening.

He joins a lengthening list of media figures felled by sexual misconduct accusations this year. Besides Rose, they include Lauer’s NBC News colleague Mark Halperin, Fox News prime-time host Bill O’Reilly and National Public Radio newsroom chief Michael Oreskes. The New York Times suspended White House correspondent Glenn Thrush last week.

The flood of allegations was set off in large part by the downfall of Hollywood studio boss Harvey Weinstein, who has been accused of sexually assaulting or harassing numerous women.

Ari Wilkenfeld, the attorney for Lauer’s accuser, praised NBC for acting “quickly and responsibly” in response to the morning host’s “egregious acts of sexual harassment and misconduct.” The lawyer did not identify his client.

Lack, in his memo, said, “We are deeply saddened by this turn of events. But we will face it together as a news organization — and do it in as transparent a manner as we can.”

An immediate challenge is filling a giant hole on a show that has long been the most lucrative for NBC News. One potential replacement, Willie Geist, on Wednesday called Lauer someone “I have always looked up to in the business, and he taught me a lot.”