Not long ago, Donald Trump and Russell Simmons were close.

The hip-hop mogul and his brother Rev. Run would fly on Trump’s private plane to Mar-a-Lago, the real estate developer’s lavish Florida resort. Simmons even had a playful nickname for Trump: Richie Rich.

When Simmons was going through a divorce, Trump’s teasing phone calls lifted his spirits.

“He’d say funny stuff,” Simmons said, adding that he had put Trump on speakerphone so that others could hear Trump’s jovial taunts about his ex-wife getting the upper hand in the divorce. “He’d say, ‘Oh, she killed you.’”

But the bond between the two men came apart this month: After Trump called for Muslims to be barred from entering the United States, Simmons denounced his onetime friend, telling him in an open letter to “stop fueling fires of hate.”

Trump’s rise in the contest for the Republican presidential nomination — which has also prompted accusations that he is using racially charged rhetoric and has drawn comparisons to the segregationist George Wallace — has created some discord among African-American celebrities whom Trump has called friends. The billionaire developer has long courted personalities from the worlds of sports and entertainment, including the boxer Mike Tyson, the former Chicago Bulls forward Dennis Rodman, and the rapper and producer Sean Combs — and he has made them part of his world in strikingly personal ways.

Some of Trump’s African-American friends and acquaintances say they are mystified by the candidate’s sweeping attacks on minority groups. In addition to his comments about Muslims, he has said Mexico sends “rapists” and other criminals to the United States; has exaggerated the role of blacks in violent crime; and suggested a Black Lives Matter protester who interrupted one of his campaign rallies “should have been roughed up” by his supporters.

While Simmons has denounced Trump, others are sticking by the candidate, saying that they were drawn to him in part because of his unvarnished personality — and his loyalty — and that they would not abandon him now.

“Hey, that’s my man. That’s who he is,” said Don King, the boxing promoter, discussing what he called Trump’s “outlandish” remarks. “To me, Donald is Donald. That’s not a presidential endorsement, but it is a humanistic endorsement,” he said.

Tyson, who is Muslim, recently defended Trump, telling the website TMZ, “Hey listen, anybody that was ever president of the United States offended some group of people.”

While Trump’s rhetoric has become more incendiary since his campaign began, his worldview was already on display over the years in his interactions with African-American friends, who have at times been forgiving of remarks that struck other audiences as insensitive.

“He’d say ‘the blacks,’ ‘the Jews,’ that stuff,’ ” Simmons recalled. “But it’s the same way people speak bluntly — like, very ‘hood. It’s semantics.”

Simmons did not publicly shun Trump in 2011, when the real estate developer showed support for those challenging President Barack Obama’s right to American citizenship and to the presidency, which many black leaders saw as an effort to undermine the legitimacy of the first African-American in the White House. After Trump spoke of a “Muslim problem” in a television interview that same year, Simmons arranged for him to meet with Muslim clerics to gain more sensitivity about their faith.

Herschel Walker, a football legend who played for the New Jersey Generals when Trump bought the team in the 1980s, and who considers him a friend, said that some of the candidate’s recent statements were being taken too literally. “I don’t think Donald is against Muslims, or blacks, or Hispanics,” Walker said. “I do know he is going to try to make this country safe.”

Trump has long relished the company of famous and successful people, seeing in their accomplishments a reflection of his own greatness, those who know him say. He likes to brag about his closeness to celebrities, once saying of Michael Jackson, who kept a home in a Trump building in Manhattan: “He follows me around, in the sense that he likes what I have.”’

King and others say that Trump tends to size up people based on whether he sees them as being of his stature, rather than according to their race.

“What matters to Trump is success,” King, 84, said in a phone interview, recalling fondly how their friendship grew from ringside encounters at boxing matches in Atlantic City. “If you are achieving success, you meet the test.”

The Rev. Al Sharpton, who has at times been friendly with Trump over the years but at others has battled with him, was more critical, suggesting that the billionaire was drawn to accomplished African-Americans for a different reason: to help his businesses.

“Black celebrities and luminaries live in a world that is much more engaging of Trump, and parallel with Trump’s world, than those of us that have been in politics and civil rights on the ground for as long as Trump has been out there,” Sharpton said. Trump had little understanding of the lives of the vast majority of African-Americans, he said.

“It’s not like there’s a Trump building in Harlem,” he added.

Trump, 69, is no stranger to racial controversy. Raised in an exclusive, nearly all-white section of Queens in an era when tribal politics dominated New York, Trump and his father were accused by the Justice Department in the 1970s of bias against black tenants in buildings they owned. They reached an agreement with the federal government in 1975.

In 1989, Trump took out full-page advertisements in four New York newspapers calling for the reinstatement of the death penalty after five men — four of them black — were arrested on charges of brutalizing and raping a white woman who was jogging in Central Park. Decades later, the five were exonerated.

As his businesses expanded in the mid-1980s, it was mostly white staff members who worked on the top floor of the Trump Organization’s offices on Fifth Avenue, recalled Jacqueline M. Williams, who was an executive assistant in her 20s at the time. Still, Williams, a Jamaican immigrant, remembered a “warm, professional environment.”

Williams, who left the company to pursue further education, said she found Trump’s recent statements “shocking” given her positive experiences with him.

In recent years, Trump has been accused of racial insensitivity by contestants on his reality show, “The Apprentice,” on NBC. One African-American contestant, Randal Pinkett, who worked for the Trump Organization for a year after winning the show’s fourth season, called race a “tremendous blind spot” for his former boss.

Still, several high-profile African-Americans, including some who have condemned the rhetoric of his campaign and his promotion of conspiracy theories about Obama’s eligibility for the presidency, appear torn about whether Trump is, at heart, a racist — or whether he is cynically playing to the anxieties of white Americans at a time of great demographic change to bolster his political standing.

Their experience is complicated, too, by the fact that Trump has extended kindness to them.

“I knew him in another life,” said the Rev. Jesse Jackson, the civil rights activist, who has known Trump for three decades and who once used office space on Wall Street donated to him by Trump. “I have never seen him in this light before.”

Jackson said that Trump’s words on the campaign trail were “devastating, painful and hurtful.” But when asked if Trump was a racist, Jackson responded, “I don’t want to use that language.”

Sharpton said he once told his godfather, the singer James Brown, that it was OK to perform at a property owned by the Trump Organization because Trump was “trying to evolve” on race. But Sharpton said he did not know whether Trump was racist, and added, “I don’t think it matters.”

“What he’s saying appeals to racists,” Sharpton said. “He’s too smart to not know what he’s doing.”

Polling about African-Americans’ views of Trump is scarce because so few blacks vote in Republican primaries. But a nationwide poll of voters released this month by Quinnipiac University found that 88 percent of black respondents answered “No” when asked if Trump “cares about the needs and problems of people like you.”

Still, those who have befriended Trump spoke with genuine affection for him in interviews, saying they had been invited into his world of jet-setting, opulent homes and a welcoming family.

Walker and Trump, for example, came from very different places — Walker is from a tiny town in Georgia — but became fast friends. Trump once accompanied Walker and his wife at the time on a visit to Walt Disney World. Walker said he had taken Trump’s children to the zoo and had visited his homes in Connecticut and Mar-A-Lago.

“We stayed together, and we always talked,” Walker said. “We were always doing something. As of today, I call him a friend.”

Simmons said he had met Trump in the 1980s “at the clubs.” “There were hot events, whatever, the cool events, where we spoke,” he said.

Over the past 20 years, he said, they spent more time together, with Simmons getting to know Trump’s family and spending time at Mar-a-Lago.

“He was a good host, that’s for sure,” Simmons said. “You’d be in the steam room and he’d come in, fully clothed, and say, ‘You guys OK in there?’ Just a nice guy.”

And Trump did not even mind his Richie Rich nickname, Simmons said. Above all, he said, Trump was fun.

King, who over the years has found himself entangled in public disputes, hostile lawsuits and accusations of fraud, said that Trump “would always be there” to defend him.

“He’s not afraid,” King said. “He’s a counterpuncher. You throw a punch at him, he’s going to throw one back.”

These days, King has Trump’s back. While acknowledging that Trump had made some mistakes in his campaign, he said that Trump was not a racist, but was merely misunderstood.

© 2015 The New York Times Company