OXFORD, Miss. — Allen Coon, perhaps the most reviled student at the University of Mississippi, was walking to his public policy class at the Trent Lott Leadership Institute on a recent weekday morning, sporting a red faux Trump cap emblazoned with the message MAKE AMERICA NATIVE AGAIN.

Mr. Coon, 21, a white man from Petal, Miss., had just cut his shoulder-length hair. It had been his visual signature on a conservative campus where the sight of a man with long hair retains some power to provoke. It had also inspired his black friends to refer to him, playfully and semi-sarcastically, as White Jesus.

Mr. Coon is aware that black people aren’t looking for a white savior. And he is acutely aware that his surname, which doubles as a racial slur, can teeter like an unexploded bomb on the lips of every Mississippian who dares to mutter it.

Yet none of that impeded Mr. Coon’s transformation into a full-blown campus celebrity in October 2015, when he helped lead the student movement that brought the Confederate-themed state flag down from the university’s main flagpole. The episode transformed Mr. Coon into a kind of stock campus character: Student agitator. Hero and villain. Subject of catcalls. Subject of memes. Someone many students loathe and many others deeply admire.

And now the country has exploded in a moment of protest unseen since the 1960s, fueled by the ascension of President Trump. It is a moment that poses fresh challenges for Mr. Coon, an ultraliberal in an ultraconservative state where emotions are running red hot but the injustices, as he perceives them, remain.

What role should he play in this new opposition? Certainly not White Jesus. How scared should he be now with his high profile and African-American girlfriend (also an activist) and habit of not shutting up?

How serious were the threats directed at him and posted on social media? There was this online comment, folksy and menacing, one of many directed at Mr. Coon after his aborted attempt in November to have Ole Miss declared a “sanctuary campus” for undocumented immigrants:

“From what I’ve read there is a large group that would gleefully use his head for a mop and his butt for a broom and God only knows what’s keeping them from it,” wrote the commenter, who identified himself as John Irwin, on the website of the Clarion-Ledger newspaper. “I guess those kids were just not raised the way I was raised.”

For Mr. Coon, there is another, more personal challenge. His critics may dismiss his convictions as P.C. posturing, but he arrived at them after witnessing the lingering prejudices that still marble the Mississippi experience, despite all of the state’s progress in the last half-century. It is a variety of political awakening that happens to some white people in the South, like a switch that flips within. Sometimes it is hard to turn off.

“I hate to say this because it sounds manic, but I can’t go through a day without obsessively thinking about race,” Mr. Coon said. “I think about it all the time, to the point that it sometimes harms my relationships with people.”

He strolled, on this mild winter morning, through the heart of campus, among the scarlet oaks and flowering dogwoods and the monument to the Confederate dead, near the place where white students rioted in 1962 as James Meredith, the school’s first black student, tried to enroll.

Even with his new haircut, and even amid the sea of white faces — Ole Miss is 77 percent white — Mr. Coon, who stands about 6-foot-4, with green eyes under heavy eyebrows, was recognized by a number of black students. Some approached and bumped knuckles. Others caught his eye from a distance, and tilted their chins his way. A subtle gesture of respect.

Mr. Coon pointed out other things he wished to see changed. Last year, the school placed an explanatory plaque in front of the Confederate monument noting that the South’s defeat freed millions. Mr. Coon would have rather seen the whole monument carted away.

He said he would like to see a new name for the campus building that currently honors James K. Vardaman, the early-20th-century Mississippi governor and United States senator who once declared, “If it is necessary every Negro in the state will be lynched; it will be done to maintain white supremacy.”

Not much better, in Mr. Coon’s eyes, is the Lott Institute, which offers a degree in public policy leadership. Its namesake, Mr. Lott, was the senator from Mississippi who resigned from his leadership post in 2002 after publicly praising the 1948 pro-segregation presidential campaign of Senator Strom Thurmond.

“This entire place is in many ways a shrine to white supremacy,” Mr. Coon said.

The fight over the flag was the kind of college experience that Mr. Coon had hoped for three years ago when he left Petal, a white-flight suburb of Hattiesburg, and enrolled at Ole Miss, founded in 1848 to educate the scions of the Mississippi planter class. As a middle school student, Mr. Coon had been a Confederate apologist, he said. But by the 12th grade, his obsession with race and racism was in full bloom, and Ole Miss beckoned to him as an American problem — one in his own backyard, one that he believed needed solving.

Ask him what flipped the switch, and he offers a laundry list: Listening to the hip-hop group N.W.A. Discovering “The Colbert Report.” The Trayvon Martin case. An act of racism by someone close to him still too raw for him to publicly share.

His two best friends were black men, and their best times were often spent crammed in a car together, where Mr. Coon was steeped in their jokes and music and passions and fears — particularly the fear of rogue police officers.

They called themselves Coon and Friends. “The joke was which one’s the coon and which one’s the friends,” one of them, Chris Stewart, 21, recalled.

Mr. Coon told them that he dreamed of making his mark. “He always told me that his biggest fear was dying and not being known for something,” said Mr. Stewart, who plays football at Wake Forest University.

Between his junior and senior years of high school, Mr. Coon attended Boys State, a mock government program, in Starkville, Miss. He was elected to the legislature, and a young black man named Malik Pridgeon was elected governor. But soon after Mr. Pridgeon’s election, the Boys State legislature learned that he was gay and sought to impeach him. Mr. Coon successfully quashed the effort. “I said, ‘Guys, if you impeach the black gay governor in Mississippi, CNN is going to be here.’”

He went on to use the filibuster to kill a school prayer bill, and another that was anti-L.G.B.T. He was granted the program’s highest award.

The next summer, Michael Brown was fatally shot by a police officer in Ferguson, Mo., and Mr. Coon was shaken. “I experienced it through social media,” he said. “I felt like I had an obligation. I felt a burden that I have to act.”

He enrolled at the university in the fall of 2014. During the previous spring semester, white students had placed a noose around the neck of the campus statue depicting James Meredith.

In the spring of 2015, Mr. Coon organized two “die-in” protests denouncing police violence. He began earning respect among black activists for his organizing talents. In the fall of 2015, he was elected to the student senate.

Some of the student activists had already demanded that the administration take down the state flag, with its prominent Confederate battle flag symbol in the upper left corner.

The activists planned to pressure the administration with protests, but Mr. Coon had another strategy. He drafted a resolution asking the administration to remove the flag, expecting it would fail and simply serve as another pressure point.

But just before the vote, a group of Ku Klux Klan members showed up on campus. People were appalled and frightened, and the measure passed easily. A few days later, on Oct. 26, 2015, police officers removed the flag on the orders of the interim chancellor at the time, Morris Stocks.

The online vitriol was intense. Mr. Coon’s responses were often laconic.

“You should be ashamed of yourself,” one man messaged him the day the flag came down. “Watch yourself Coon.”

Mr. Coon’s reply: “Don’t care John.”

Other critics are more respectful. Dylan Wood, 20, a junior from Tupelo, Miss., said removing the state flag from the flagship state university was “a slap in the face” to his taxpaying family. “Personally, I like him,” he said, “but Allen Coon is one of the most disliked people on campus.”

There are also fans. On a recent afternoon, Correl Hoyle, an African-American senior, was sitting under the statue of Mr. Meredith with one of a series of signs that he displays in an effort to inspire conversation. (On that day, the sign quoted Prince: “Dearly beloved…”) He said he had spent some time under the statue nearly every school day since the noose episode.

Mr. Hoyle said the flag would never have come down had a white man not been perceived as the leader of the movement. With a black leader, Mr. Hoyle said, it would have been “like the Black Lives Matter movement all over again: People would say, ‘Oh, you’re being overdramatic.’”

Dominique Scott, a sociology major from Texas who was active in the fight against the flag, counts Mr. Coon as a close friend and credits him for his courage and conviction. But she has had words with him about the way the news cameras and the reporters all flocked to him first.

“Coon was not constantly combating that narrative of the white savior,” she said. “When they’d say, ‘You’re so wonderful,’ he wouldn’t do that. He’d just accept the praise and go about his business.”

Mr. Coon is still contemplating such criticism and what it means for his future. Though he had announced that he would reintroduce his sanctuary campus bill in the student senate, he walked the idea back in an interview this month.

“It does eventually become problematic,” he said, “that a white man is leading the charge.”

As a junior with a double major in public policy and African-American studies, he has watched with interest as Democrats in the Mississippi Legislature introduced bills to change the design of the state flag this year. But he knows that in a Republican-controlled Legislature, that change is unlikely to happen.

Mr. Trump’s election has pushed him further left. “I’ve been exposing myself to much more radical politics and ideologies,” Mr. Coon said. “I follow some anarchists and socialists on Twitter.”

In Oxford, there are certain places he will not go anymore — football games, the town square — because he has learned that the likelihood of an ugly confrontation is too great. But he is not an outcast on campus. His social circle consists mostly of black students and activists — the alternative Ole Miss.

“There’s several organizations on campus that the progressives bundle in together,” he said. “I’d argue that there are a lot of liberal-leaning and liberal-identifying people on campus. But the majority of students feel uncomfortable expressing those views, especially those who are in a Greek organization.”

He has been getting serious with his studies. He is getting serious with his girlfriend. He thinks about the children he may have one day. He thinks about their skin tone, and whether he would ever give them his surname.