Kevin Johnson Jr. was born on September 23, 1985. He grew up in a modest neighborhood in the St. Louis, Missouri area. 

On July 5, 2005, police were looking for Kevin Johnson for violating his probation. While they were searching his house, Johnson's 12-year-old brother, known as "Bam Bam," had a seizure. Johnson claimed that the police prevented his family from helping his brother. Bam Bam later died in the hospital. Johnson believed the police were to blame for this.

Later that day, Sergeant William McEntee, one of the officers involved, returned to the area. He had gone there on a complaint about fireworks. Johnson approached McEntee and opened fire on him, hitting him multiple times. McEntee managed to drive a short distance before crashing his car. Johnson then walked up to the car and shot McEntee again. McEntee later died in the hospital.

In the years following the murder, Johnson faced trial and was convicted of first-degree murder. His lawyers argued that his death sentence was influenced by racism because Johnson is Black and McEntee was white. They noted that the prosecutor sought death penalties more often in cases involving Black defendants. However, the courts did not agree and refused to stop the execution.

Johnson's daughter, Khorry Ramey, requested to witness her father's execution but was denied because Missouri law prohibits anyone under 21 from being present during an execution. Kevin Johnson was executed on November 29, 2022, by lethal injection. In his final statement, he expressed apologies to the families of both McEntee and his own. Remarkably, he had a spiritual adviser with him during the execution, a first in Missouri's execution history.