When Michael Brown Jr., an unarmed Black teenager, was fatally shot in 2014 by a white police officer and his body left in the street under the August sun, the small St. Louis suburb of Ferguson roiled and plunged into crisis.

Community grief, long-simmering fury and distrust of government gave way to waves of protests that continued for months. There were violent confrontations between protesters and heavily armed law enforcement officers. A neighborhood convenience store was looted and burned to the ground. The protests drew activists from across the nation, amplified the national Black Lives Matter movement and fueled larger questions about race in America.

And at a more grass-roots level, it created a political incubator of emerging local leaders: A new generation of young protesters who came of age during the Ferguson uprising have found ways to chip away at the racial disparities in Ferguson and nearby St. Louis, shifting from protests to politics and policies.

Since Mr. Brown’s death, Ferguson elected its first Black mayor. The police chief and more than half of the police officers are Black. And St. Louis County elected its first Black prosecutor.

“Ferguson gave birth to all kinds of young people who were committed to civil rights and social justice and representation,” said Kimberly Norwood, a Washington University law professor and editor of “Ferguson’s Fault Lines: The Race Quake That Rocked a Nation.”