Chris Harrison, the longtime host of “The Bachelor,” “The Bachelorette” and “Bachelor in Paradise,” has parted ways with the reality TV franchise after nearly 20 years as its most constant presence.

His departure, which was first reported by Deadline on Tuesday, comes several months after a much-criticized exchange with a previous Bachelorette about racism, which led Mr. Harrison to step back temporarily from his role as host. It also immediately follows Monday night’s premiere of the first season not hosted by Mr. Harrison since the series’ debut in 2002.

Mr. Harrison was fundamental to the narrative arc of each season of “The Bachelor” and its spinoff shows, playing the role of M.C., conflict mediator and even onscreen dad to the contestants — all while talent scouting and orchestrating drama, with the help of producers, behind the scenes.

“I’ve had a truly incredible run as host of The Bachelor franchise and now I’m excited to start a new chapter,” Mr. Harrison wrote on Instagram on Tuesday. “I’m so grateful to Bachelor Nation for all of the memories we’ve made together. While my two-decade journey is wrapping up, the friendships I’ve made will last a lifetime.”

Warner Horizon and ABC Entertainment, which produce and distribute the series, wrote in an email statement: “Chris Harrison is stepping aside as host of ‘The Bachelor’ franchise. We are thankful for his many contributions over the past 20 years and wish him all the best on his new journey.”

The Deadline story alluded to an eight-figure payout for Mr. Harrison, which The Times could not confirm.

Mr. Harrison’s exit was prefigured in an announcement in February that he would be “stepping aside” from the show “for a period of time” after a heated conversation with Rachel Lindsay, the first Black Bachelorette, in which he downplayed her concerns about the past conduct of Rachael Kirkconnell, a contestant on this year’s season of “The Bachelor.”

Before the series finale, a photo had surfaced of Ms. Kirkconnell attending an “Old South” antebellum-themed sorority party in 2018, where she and other attendees dressed in period attire. Ms. Kirkconnell, who is white, was a clear front-runner on Matt James’s season — the first with a Black male lead. (She eventually received the final rose.)

Ms. Lindsay had expressed concerns about Ms. Kirkconnell’s attendance of such an event, as well as that she had not thought to tell Mr. James about it. Mr. Harrison vigorously and reflexively defended Ms. Kirkconnell, suggesting that she wouldn’t have known better in 2018.

He assailed Ms. Kirkconnell’s critics as being “judge, jury, executioner.”

“People are just tearing this girl’s life apart,” he said. “It’s just unbelievably alarming to watch this.”

He later apologized on Instagram. “I invoked the term ‘woke police,’ which is unacceptable,” Mr. Harrison wrote, adding, using an abbreviation for Black and Indigenous people and people of color: “I am ashamed over how uninformed I was. I was so wrong. To the Black community, to the BIPOC community: I am so sorry. My words were harmful.”

“This historic season of ‘The Bachelor’ should not be marred or overshadowed by my mistakes or diminished by my actions,” he wrote.

Ms. Kirkconnell also posted an apology on Instagram. While she did not directly confirm the veracity of the party photos or other content posted online, she said her actions had been racist.

“I’m here to say I was wrong,” she wrote in her post. “I was ignorant, but my ignorance was racist.”

The interaction between Mr. Harrison and Ms. Lindsay was notable because the “Bachelor” franchise had long been criticized for its lack of diverse contestants. Before Ms. Lindsay’s season, nearly all of the previous 33 Bachelors and Bachelorettes had been white.

And as the Bachelorette, Ms. Lindsay could not escape racism in the form of microaggressions and, seemingly, sabotage. One potential suitor greeted her by saying, “I’m ready to go Black and I’m never going to go back,” and another referred to her as “a girl from the hood.” A third contestant, Lee Garrett, bad-mouthed several Black contestants to Ms. Lindsay, using words including “aggressive,” “big,” “angry” and “violent.” (Tweets attributed to Mr. Garrett that surfaced during Ms. Lindsay’s season equated the NAACP with the KKK.)

At the time of Mr. Harrison’s exchange with Ms. Lindsay over the “Old South” party in February, she was a correspondent on “Extra,” interviewing him for the show.

After, Ms. Lindsay addressed the interaction on a podcast she co-hosts. She said Mr. Harrison had apologized to her but said she was “having a really, really hard time” accepting his apology.

“I can’t take it anymore,” she said, speaking broadly about her frustration with the franchise’s handling of race. “I’m contractually bound in some ways, but when it’s up — I am so — I can’t, I can’t do it anymore.”

Though the franchise has not named a permanent replacement host, there are some temporary ones lined up for the next few seasons. This season of “The Bachelorette” is hosted by Tayshia Adams and Kaitlyn Bristowe, two former Bachelorettes. When it airs this summer, “Bachelor in Paradise” will be guest-hosted by David Spade.