BALTIMORE — Prominent Black Lives Matter activist DeRay McKesson was released Sunday after a night in jail following his arrest in Baton Rouge while protesting the police killing of a black man.

McKesson, 31, had traveled to Louisiana from Baltimore, where he grew up and returned last year after the death of Freddie Gray, the black man whose broken neck inside a police van sparked riots and upheaval. He waged an unsuccessful campaign for mayor this spring.

He now works for Baltimore public schools as interim chief of human capital, responsible for staffing and dealing with reform. Schools CEO Sonja Santelises said that his activism “is part of who he is, it’s part of what drives him, and it’s part of what drives him to move the work for kids.”

Arrest in Baton Rouge

Brittany Packett, an activist who was with him Saturday night, said McKesson was arrested while marching for Alton Sterling, a 37-year-old black man who was killed after two white officers tackled him outside a convenience store. Video of the shooting in Baton Rouge on Tuesday was posted online.

Packett told The Associated Press that police “intentionally provoked” the protesters. She said McKesson, who was wearing bright red shoes, was taken away after an officer said, “you with the loud shoes — if you step back into the street you’ll be arrested.” She said several officers then tackled him, even though he wasn’t in the street.

Booking documents provided by the East Baton Rouge Sheriff’s Office say McKesson was arrested on a charge of obstructing a highway. A police affidavit of probable cause says McKesson “intentionally” placed himself in the road after protesters were repeatedly warned by loudspeaker to remain on private property or the curb.

“During the protest, the defendant entered the roadway and was provided another verbal order to exit the lanes of travel. Moments later, the defendant entered the roadway again and was taken into custody by officers on scene without incident,” the affidavit said.

McKesson thanked supporters after his release on bond Sunday afternoon.

“At times, all 50 of us were in one cell, unable to all sit, sleeping on the floor or under the benches. But our spirits remained strong,” he tweeted.

Educator to activist

Mckesson is one of the most recognizable faces to emerge from the Black Lives Matter movement — a former educator who built a national following after leaving his home and job in Minneapolis in August 2014 for Ferguson, Missouri, to document the rising anger over race relations following a white officer’s fatal shooting of Michael Brown, an unarmed black man.

Mckesson was born to drug-addicted parents in Baltimore. His father got clean and moved him to Catonsville, a predominantly white suburb. After high school, Mckesson attended Bowdoin College in Maine.

Mckesson then taught sixth grade in Brooklyn through Teach for America, which places college graduates in poor districts for two-year commitments. He later returned to Baltimore and launched an after-school program before joining the public school system in an administrative job.

He left again in 2013, this time for the Minneapolis school system. When Brown was shot, Mckesson drove 500 miles (800 kilometers) to Ferguson.

Being on the streets, he said, “woke me up.” And so Mckesson returned to Baltimore, with the promise of a spare room at a family friend’s home and a plan to run for mayor.

Dive into politics

Before he finished a distant sixth among 13 Democrats in the April primary, his agenda included establishing a network of community first-responders to de-escalate violence, and hiring people affected by police brutality to train officers on racism and community engagement.

“People want hope. They want transparency … a mayor who has a plan, who understands the issues deeply,” the candidate said.

But McKesson was met with resistance and skepticism. Some of Baltimore’s longtime activists criticized him for not engaging with them, and questioned whether his campaign was merely a ploy to grow his “brand.”

“Who sent you and who will you serve?” Jamye Wooten, founder and publisher of an online forum linking social justice issues and faith communities, asked in a blog post. “Here you earn your stripes by serving and being in the community when there are no cameras.”

The future

McKesson’s Twitter handle @DeRay now counts more than 450,000 followers, and he was one of the Black Lives Matter activists and civil rights leaders who met with President Obama at the White House.