COLUMBIA, Mo.

The University of Missouri’s president stepped down Monday, and its chancellor moved aside, after protests by the school’s students and football team over alleged inaction against racial abuse on campus.

President Tim Wolfe’s high-profile resignation, followed hours later by news that Chancellor R. Bowen Loftin would move to a new job, was the latest shock to the state of Missouri, and the United States at large, which has been roiled for more than a year by racial tensions after a white police officer shot and killed an unarmed black teen in nearby Ferguson, Mo., in August 2014.

Then, as demonstrations continued at the university and spread to other college campuses across the country, a suspect was taken into custody on Wednesday for making online threats to shoot African-Americans at the university.

The announcement followed a post on the social media smartphone app Yik Yak on Tuesday, tagged for the college town of Columbia.

The posting read: “I’m going to stand my ground tomorrow and shoot every black person I see.”

In a campuswide alert early Wednesday, police said they had apprehended the suspect, Hunter Park, a 21-year-old student at the Missouri University of Science and Technology in Rolla, about 100 miles south of Columbia, on suspicion of making a terroristic threat on the social network.

They said the suspect “was not located on or near the MU campus at the time of the threat.”

The threat prompted stepped-up security on the university campus, but classes were operating on a regular schedule, authorities said.

Unrest at the university, widely known as “Mizzou,” started on Sept. 12 when Payton Head, president of the Missouri Student Association, said on his Facebook page that vile, anti-black slurs were hurled at him by someone in a pickup truck while he walked on campus. He said the university did not address the incident for nearly a week.

His post went viral, and the lack of any strong reaction by Mr. Wolfe as head of the four-campus university system, led to demonstrations at the school’s homecoming parade in early October. At the time, about 10 African-American students linked arms in front of the red convertible that Mr. Wolfe was riding in during the parade. According to local news reports, as they blocked the car, they took turns reciting points in history where MU students had endured discrimination.

Instead of talking with students, Mr. Wolfe tried to drive around them, a video of the demonstration shows. The president’s driver didn’t get past the line, but hit one of the student demonstrators with the car.

Mr. Wolfe, according to the video, watched as onlookers manhandled the students and yelled at them. Columbia police also threatened the protesters with pepper spray while Mr. Wolfe remained seated in the car.

Mr. Wolfe’s handling of the entire incident drew protests from students.

Also last month, a swastika drawn in feces was found at a university dormitory, according to the Residence Halls Association.

Protests reached a critical point last weekend when the university’s black football players refused to practice or play until Mr. Wolfe stepped down. Some teachers and students also threatened to boycott classes.

In a televised news conference on Monday held to announce his resignation, an emotional Mr. Wolfe said, “I take full responsibility for this frustration and I take full responsibility for the inaction that has occurred.”

“My decision to resign comes out of love, not hate,” he added, quoting passages from the Bible. “Please, please use this resignation to heal, not to hate.”

Up until Monday, Mr. Wolfe had shown no inclination to resign, although he had acknowledged change was needed and had planned a new “diversity and inclusion strategy” to be released in April.

The university’s board also issued an apology later on Monday and said that Chancellor Loftin would relinquish that role and take up the new job of director for research facility development on Jan. 1.

“To those who have suffered, I apologize on behalf of the university for being slow to respond to experiences that are unacceptable and offensive in our campus communities and in our society,” Donald Cupps, chair of the University of Missouri Board of Curators, said in a statement.

On Tuesday, the university named Chuck Henson, a black law professor and associate dean, as its first interim vice chancellor for inclusion, diversity and equity. The appointment followed an emergency meeting of the four-campus system’s governing board Monday. The meeting concluded with promises of restoring a “culture of respect” while providing additional, though unspecified, support for aggrieved students and a renewed commitment to bolster minority hiring and recruitment.

The football team, nicknamed the Tigers, suspended practice last Saturday and Sunday, and more than 30 black players had vowed not to return until Mr. Wolfe resigned or was fired.

That would have been a financial hit to the university, which, under its contract, would have had to pay $1 million to its next opponent, Brigham Young University, if the Tigers failed to play.

Football activities resumed on Tuesday in preparation for Saturday’s game against Brigham Young.

In addition to the team’s action, graduate student Jonathan Butler held a weeklong hunger strike, which he ended on Monday.

“It should not have taken this much, and it is disgusting and vile that we find ourselves in the place that we do,” Mr. Butler told reporters on campus after Mr. Wolfe announced his resignation.

Protests on campus had been led by a group called ConcernedStudent1950, which says African-American students have endured decades of racial slurs and believes white students benefit from favoritism in many aspects of campus life.

The group, which takes its name from the year the university first admitted African-American students, on Monday demanded an immediate meeting with the university’s faculty council, Board of Curators and the governor of Missouri to discuss shared governance of the school.

“While today may seem bright to some, this is just a beginning in dismantling systems of oppression in higher education, specifically the UM system,” Marshall Allen, a member of the group, told more than 500 people gathered on campus.

“This was the right decision to help the university turn the page, and for its leaders to recommit to ending racism on campus,” U.S. Sen. Claire McCaskill of Missouri, a Democrat and graduate of the school, said in an emailed statement.

Missouri Gov. Jay Nixon, also a Democrat, welcomed the move.