Chris Matthews, the veteran political anchor and voluble host of the long-running MSNBC talk show “Hardball,” resigned on Monday night, an abrupt departure from a television perch that made him a fixture of politics and the news media over the past quarter-century.
Mr. Matthews, 74, had faced mounting criticism in recent days over a spate of embarrassing on-air moments, including a comparison of Senator Bernie Sanders’s campaign to the Nazi invasion of France and an interview with Senator Elizabeth Warren in which the anchor was criticized for a condescending and disbelieving tone.
On Saturday, the journalist Laura Bassett wrote for GQ magazine online that Mr. Matthews had made inappropriate comments about her appearance in the makeup room of his studio on several occasions when she was a guest on his program.
On Monday, a solemn Mr. Matthews began his usual 7 p.m. broadcast by announcing to his viewers, “I’m retiring — this is the last ‘Hardball’ on MSNBC.”
In a brief monologue, he said he had agreed to step down “after conversations” with network executives, adding that his exit “isn’t for a lack of interest in politics.” He also acknowledged giving “compliments on a woman’s appearance that some men, including me, might have once incorrectly thought were OK.”
“For making such comments in the past, I’m sorry,” Mr. Matthews said.
His sudden signoff, though negotiated with senior network executives, came as a shock to some of Mr. Matthews’s most prominent on-air colleagues. Steve Kornacki, the anchor tasked with hosting the remainder of Monday’s “Hardball” episode, appeared stunned as the show returned from a commercial break.
“Um, that was a lot to take in,” Mr. Kornacki said, his eyes wide. “I’m sure you’re still absorbing that, and I am, too.”
The anchor and correspondent Katy Tur posted a note on Twitter about Mr. Matthews’s departure and added the caption: “Wait. What?”
An MSNBC spokesman said on Monday that a rotating series of hosts would fill Mr. Matthews’s time slot until a permanent replacement was found.
Mr. Matthews is an eminence grise of television news, his pugilistic and red-cheeked persona familiar to viewers from countless election nights and parodies on shows like “Saturday Night Live.” He spoke from experience: Before his move into punditry, Mr. Matthews served as a speechwriter in Jimmy Carter’s administration and spent years as chief of staff to Thomas P. O’Neill Jr., the powerful Democratic speaker of the House in the late 1970s and much of the ’80s.
But executives at MSNBC had been discussing a potential retirement plan for Mr. Matthews for months, according to two people familiar with internal network discussions. There was talk of shifting “Hardball” to a less prominent time of day, during MSNBC’s afternoon lineup.
That was before Mr. Matthews faced a sustained bout of online criticism for his on-air comportment in recent weeks. On the previous Monday, he opened “Hardball” by apologizing to viewers for a clumsy metaphor that compared Mr. Sanders’s dominance in the Nevada caucuses to Germany’s takeover of France in World War II.
“In the days and weeks and months ahead, I will strive to do a better job myself of elevating the political discussion,” Mr. Matthews pledged to viewers that night.
But days later, he was under fire again, this time after Ms. Bassett’s article in GQ, in which she said Mr. Matthews, in a makeup room, had looked at her and asked, “Why haven’t I fallen in love with you yet?” She described other comments that had made her uncomfortable, writing, “It undermined my ability to do my job well.”
On Saturday, Mr. Matthews had been scheduled to appear as part of MSNBC’s coverage of the South Carolina primary.
Instead, he was absent. Mr. Matthews had been benched, according to a person briefed on private network conversations.
Marc Tracy contributed reporting.