Ms. Maddow — whose program is MSNBC’s No. 1 ratings draw — represents the biggest name in the NBC family to express misgivings over the network’s handling of Mr. Farrow’s reporting. Her on-air statements on Friday were likely to increase pressure on the NBC News leadership team, including the chairman, Andrew Lack, and the news division president, Noah Oppenheim, who have faced scrutiny from the press and inside network headquarters at 30 Rockefeller Plaza.

“The allegations about the behavior of Harvey Weinstein and Matt Lauer are gut-wrenching,” Ms. Maddow said on Friday night. “But accusations that people in positions of authority in this building may have been complicit in some way in shielding those guys from accountability — those accusations are very, very hard to stomach.”

Additionally, Ms. Maddow expressed misgivings over what executives knew about Mr. Lauer’s behavior before his firing in November 2017.

In May 2018, several months after NBC fired Mr. Lauer, NBC Universal released the findings of an investigation that absolved top news executives. “We found no evidence indicating that any NBC News or ‘Today’ show leadership, News H.R. or others in positions of authority in the News Division received any complaints about Lauer’s workplace behavior prior to Nov. 27, 2017,” the report said.

But the report also created a backlash, because it was overseen by NBC Universal’s chief counsel, Kimberley D. Harris. Other media organizations that have faced accusations of workplace misconduct in recent years, including Fox News, CBS and NPR, hired outside law firms to conduct investigations.

Mr. Farrow, in “Catch and Kill,” reported that NBC had issued secret settlements to other women who had complained about Mr. Lauer, a charge executives have vehemently denied.

“As far as we can tell, there has never been an independent investigation of that,” Ms. Maddow said. “So until there is an independent investigation — if there’s ever going to be one — that remains NBC’s word versus Ronan Farrow’s reporting and assertions.”