When Chris Licht faced criticism for his management of CNN, from both inside the newsroom and beyond, he had every reason to believe that his close personal relationship with David Zaslav, the chief executive of the network’s parent company, would protect him.

He was wrong. He was also not alone.

Mr. Zaslav, who took over Warner Bros. Discovery last year, has cultivated an astonishing number of influential friends in the media industry and elsewhere. Some say they call, text or email him daily or almost daily. But the tumultuous personnel changes at CNN under Mr. Zaslav’s leadership make clear that a Zaslav friendship, no matter how deep or longstanding, has its limits.

Jeff Zucker, replaced as CNN’s chief executive by Mr. Licht, frequently described himself as Mr. Zaslav’s best friend. They no longer talk or text on a daily basis.

Don Lemon, the longtime host, socialized with Mr. Zaslav in New York and the Hamptons. CNN ousted Mr. Lemon in April.

Brian Stelter, CNN’s chief media correspondent, had regular breakfasts and lunches with Mr. Zaslav for years. CNN canceled his show, and Mr. Stelter left the network, in August 2022.

Chief executives fire even close subordinates all the time, one reason the job at the top is often described as lonely. And Mr. Zaslav has defended his decisions to dispatch some of his friends, sometimes in large group meetings. As he said to a group of Warner Bros. studio executives: “It’s not show friends — it’s show business,” quoting Jerry Maguire’s cutthroat protégé from the hit 1996 film.

Still, it’s rare that a corporate leader ousts close personal and social friends. The tumult in Mr. Zaslav’s friendships, which hasn’t been fully dissected until now, provides crucial context for the off-camera drama that has roiled CNN the last two years.

This account of his interactions with leading figures at CNN is based on interviews with more than a dozen people with knowledge of the network’s inner workings.

In a statement, a Warner Bros. Discovery spokesman didn’t address Mr. Zaslav’s relationship with the former CNN employees. The spokesman said, “The network continues to make meaningful strides in transforming itself for the future under the leadership of new chairman and C.E.O., Mark Thompson.” He cited the network’s recent higher ratings, its streaming debut and its new programming lineup as signs of momentum.

Through representatives, Mr. Zucker, Mr. Licht, Mr. Lemon and Mr. Stelter declined to comment.

Mr. Zucker and Mr. Zaslav had bonded more than a decade ago at NBCUniversal, where Mr. Zucker was head of the TV division and Mr. Zaslav was president of the lucrative cable division. They golfed together, and both had houses in the Hamptons. When Mr. Zaslav presented Mr. Zucker with an award at a ceremony in 2019, Mr. Zucker called him “the best friend that anyone could ever want, and I’m lucky that he’s mine.”

Mr. Zaslav was named the incoming chief executive of the soon-to-be-christened Warner Bros. Discovery — after the merger of Discovery and WarnerMedia, CNN’s parent — in May 2021. After the deal was struck, Mr. Zaslav publicly praised Mr. Zucker, calling him a “hugely talented guy” and adding, “We’ll see what he wants to do.”

But even before the deal closed, Mr. Zaslav was contemplating options for replacing Mr. Zucker. Mr. Zucker was widely viewed inside CNN, which he had led since 2013, as unlikely to steer it in the new direction desired by Mr. Zaslav, who thought the network had become too partisan and anti-Trump.

There were early signs of tension between Mr. Zucker and Mr. Zaslav.

On a golf trip in the fall of 2021, Mr. Zaslav, Mr. Zucker and others discussed over lunch whether CNN had tilted in a partisan direction, with some saying it had. Mr. Zucker pushed back, saying he didn’t see any need for CNN to change its editorial direction. Given Mr. Zaslav’s plans for the network, it seemed obvious that Mr. Zucker would chafe under his new boss, a participant said.

John Malone, an influential Discovery shareholder, gave an interview to CNBC in November 2021 saying he wanted CNN to “evolve back to the kind of journalism that it started with,” an implicit rebuke of Mr. Zucker’s tenure. Mr. Zaslav called Mr. Zucker and made light of the comments to assuage his friend, according to two people familiar with the call. Later that year, Mr. Zucker suggested that Mr. Zaslav consider selling the network; Mr. Zaslav had no intention of doing that.

With Mr. Zucker still running CNN, Mr. Zaslav started talking to his protégé, Mr. Licht, about taking Mr. Zucker’s job in late 2021, people familiar with his recruitment said. Mr. Zaslav also spoke with John Stankey, the chief executive of AT&T, which owned WarnerMedia at the time, about taking CNN in a different direction, multiple people with knowledge of the exchange said. While Mr. Zaslav wasn’t any more explicit, the suggestion seemed to be that Mr. Zucker had to go. An AT&T spokesman declined to comment.

But then Mr. Zucker made that move unnecessary: He was forced out of the network in February 2022 after violating company policies, including failing to disclose a consensual relationship with a top CNN executive. AT&T gave Mr. Zaslav a heads-up, but he otherwise had no involvement in the decision.

In the days and weeks after leaving CNN, Mr. Zucker heard nothing from Mr. Zaslav aside from a single text message. About a year later in March, both men were coincidentally staying at the Faena Hotel in Miami Beach. What happened next would become the subject of much discussion among confidants of the two men.

After Mr. Zucker texted Mr. Zaslav to meet up and clear the air, the two met at the hotel. Mr. Zucker told Mr. Zaslav that he had just come through a difficult period, perhaps the worst of his life, and said his closest friends were there for him, according to several people briefed on the conversation. “The one who wasn’t there …,” Mr. Zucker said before Mr. Zaslav finished the sentence: “Was me.”

Mr. Zaslav maintained that he couldn’t reach out because the merger hadn’t closed and it might appear that he was interfering. Mr. Zucker said he didn’t want Mr. Zaslav to interfere. He wanted him to call and say he was thinking of him and felt bad for him.

For his part, Mr. Zaslav complained that Mr. Zucker was telling people that Mr. Zaslav was behind his removal. That wasn’t true, Mr. Zaslav said, and told Mr. Zucker that he had to let that go.

Afterward, Mr. Zaslav texted Mr. Zucker, thanked him and said, “Let’s move forward.”

But in a call with Mr. Licht after the meeting, Mr. Zaslav belittled Mr. Zucker as a weakling who had tears in his eyes, several people with knowledge of the conversation said. “Can you believe this?” Mr. Zaslav asked, injecting an expletive.

Mr. Zucker and Mr. Zaslav have only occasionally spoken since. But Mr. Zucker’s former wife, Caryn, attended Mr. Zaslav’s 63rd birthday party at the Beverly Hills restaurant Mr. Chow in January.

When Mr. Licht was named head of CNN in late February 2022, audience research reviewed by Mr. Zaslav suggested that several prominent CNN personalities were identified with CNN’s partisan tilt, among them Mr. Stelter and Mr. Lemon, according to a person privy to discussions about on-air talent.

In August 2022, CNN announced that it was ending Mr. Stelter’s “Reliable Sources” and that he was leaving the network. As Mr. Stelter stepped off the set after his final show, Mr. Zaslav called him and said he was “taking a lot of heat” for the decision. Mr. Stelter put the call on speakerphone. “Buddy, you’re a great talent,” Mr. Zaslav said, and suggested that they might work together again, according to three people familiar with the exchange. It was Mr. Licht’s decision to get rid of Mr. Stelter, but he had briefed Mr. Zaslav on his plan and Mr. Zaslav didn’t intervene, two people familiar with the decision said.

Mr. Lemon was another matter. Firing CNN’s prominent Black gay anchor could be a public-relations nightmare and immediately taint Mr. Licht’s tenure. Mr. Licht sought to protect Mr. Lemon by moving him from his 10 p.m. slot to a revamped morning show, three people familiar with his thinking said.

Mr. Lemon wasn’t happy about the morning show, but he still considered Mr. Zaslav his friend and protector, according to two people aware of his thinking. After they met in the city in 2011, Mr. Zaslav showered Mr. Lemon with gift boxes and invitations to social events, including his Labor Day parties. Some weekends Mr. Zaslav dropped in on Mr. Lemon just to hang out, and Mr. Zaslav invited him to walk on the beach. Mr. Lemon often called and texted Mr. Zaslav and felt free to criticize Mr. Licht, telling Mr. Zaslav that Mr. Licht was losing the confidence of CNN’s newsroom.

Then Mr. Lemon committed an on-air gaffe. In February, he suggested that Nikki Haley, a 51-year-old presidential candidate, “isn’t in her prime,” since a woman is in her prime only “in her 20s and 30s and, maybe, 40s.” In the ensuing uproar, Mr. Licht reprimanded Mr. Lemon but tried to protect his job. Finally, Mr. Zaslav’s patience ran out: “Why hasn’t he been fired?” Mr. Zaslav demanded, lacing the question with profane language, according to people familiar with his remarks.

By early March, Mr. Zaslav had promised Warner Bros. Discovery board members that Mr. Lemon would be off the morning show before Memorial Day.

Mr. Licht tried to find a job for Mr. Lemon at another Warner Bros. Discovery TV network, multiple people said. But after continuing pressure from Mr. Zaslav, Mr. Licht announced on April 24 that CNN and Mr. Lemon had “parted ways.” Neither Mr. Zaslav nor Mr. Licht personally broke the news to Mr. Lemon, although Mr. Licht offered to meet with him after they told his agent.

That meeting never happened, but Mr. Zaslav and Mr. Lemon subsequently met at Barney Greengrass, Mr. Zaslav’s usual breakfast place on the Upper West Side of Manhattan. Mr. Zaslav said he was sorry for the way Mr. Lemon had been treated and blamed Mr. Licht for the outcome, according to three people familiar with their talk. While the discussion was cordial, the two no longer socialize.

It never seemed to occur to Mr. Licht that his own friendship with Mr. Zaslav might not protect him, and no wonder: A spokesman for Warner Bros. Discovery told The New York Post that “Chris has Zaslav’s full support,” and Mr. Zaslav made many similar statements. But soon after hiring him, Mr. Zaslav had bluntly said: “We’ve been friends for 15 years. We’re not friends anymore. You work for me.”

Signs of trouble brewed soon after.

Just before Thanksgiving last year, The New York Post reported that Mr. Licht, in a staff meeting, said on-air talent, including Mr. Lemon, wouldn’t be able to drink on New Year’s Eve, though the hosts Andy Cohen and Anderson Cooper would be exempt. Mr. Zaslav, an avid reader of The Post, was angry and wanted a correction — no one was going to be drinking on air that year, and Mr. Licht’s comment about the two hosts had been in jest.

Nathaniel Brown, the chief communications officer for Warner Bros. Discovery, convened a conference call with a group of top executives including Mr. Zaslav and Mr. Licht. Mr. Licht had just landed in Abu Dhabi for an approved business trip.

The group decided not to go back to The Post. Nonetheless, Mr. Zaslav lost his temper. “Where are you?” he demanded of Mr. Licht. Mr. Licht said he was in Abu Dhabi. “Why are you in Abu Dhabi? You need to be back” at CNN headquarters, Mr. Zaslav said, according to several participants on the call.

Mr. Licht returned to the airport less than 24 hours after arriving.

Mr. Zaslav and Mr. Licht also clashed after CNN said in January that Laura Coates, then CNN’s on-air senior legal analyst, would be the sole anchor of the 11 p.m. hour. Mr. Zaslav loves sports metaphors, and often described CNN as the “world class” news equivalent of the New York Yankees. He told Mr. Licht that he wanted great players on the field and that Mr. Licht should go for big names, several people with knowledge of the exchange said.

Although the decision was up to Mr. Licht, who defended Ms. Coates, the clear implication was that she didn’t measure up. When Mr. Licht told his staff that Ms. Coates would not be the 11 p.m. anchor after all, some suspected the decision was Mr. Zaslav’s. But during the meeting, Mr. Licht attributed the decision to budget constraints. (Ms. Coates finally did get the 11 p.m. slot: “Laura Coates Live” debuted last month.)

In a statement, Warner Bros. Discovery said “any suggestion that Mr. Zaslav was not supportive of Ms. Coates or her role at the network is wholly inaccurate.”

Last spring, CNN landed former President Donald J. Trump for a televised “town hall” interview — proof, if any were needed, that the network had shed any partisan leanings. Mr. Zaslav was thrilled.

The day after the broadcast, in which a rabidly pro-Trump audience cheered his remarks throughout, Mr. Zaslav called Mr. Licht to say he had just had his “best week ever” running the network. Within a week, as criticism of the event mounted, Mr. Zaslav’s enthusiasm cooled.

Then came a long profile of Mr. Licht in The Atlantic. Mr. Licht criticized the newsroom’s coverage of the Covid-19 crisis and of Mr. Trump and told his personal trainer that Mr. Zucker “couldn’t do” Mr. Licht’s workout routine. The article alienated most of his remaining supporters at the network.

That same week, Mr. Zaslav warned Mr. Licht that he had lost control of the narrative and had six months to regain it, according to people familiar with the conversation.

Mr. Licht’s promised six months turned into less than six days. The next week, Mr. Zaslav told the board that he was replacing Mr. Licht, multiple people familiar with the message said. Soon after, he invited Mr. Licht for an early-morning walk in Central Park and broke the bad news, acknowledging that both he and Mr. Licht had made mistakes over the previous year.

Their abbreviated walk ended by West 72nd Street. Mr. Zaslav reminded Mr. Licht that he had said they were no longer friends once Mr. Licht worked for him. “Now that I’m not your boss anymore, I hope we can be friends again,” Mr. Zaslav said, and the two men hugged.

Mr. Zaslav replaced Mr. Licht with Mr. Thompson, a former chief executive of The New York Times and director general of the BBC.

The two have never been friends.