Ernest Lee Johnson was born on August 20, 1960, in Steele, Missouri. He was raised by his grandmother in Charleston, Missouri. His early life was affected by his mother’s struggles with substance abuse, including alcohol addiction. Because of this, Johnson was born with fetal alcohol spectrum disorder, which affected his development.

As he grew up, Johnson faced numerous challenges. His childhood experiences and family situation likely contributed to difficulties throughout his life. In his adult years, he got into trouble with the law. Johnson was arrested and imprisoned for robbery and burglary. After serving time, he was released on parole in May 1993.

On February 12, 1994, Ernest Lee Johnson attempted to rob a Casey's convenience store in Columbia, Missouri. During this robbery, he killed three employees: Mary Bratcher, Mable Scruggs, and Fred Jones. Johnson had borrowed a .25-caliber pistol to carry out the crime. While he attempted to access the safe, Bratcher tried to destroy a key to it, which made Johnson angry.

In response, he shot all three victims. After shooting them, he used a claw hammer to beat them to death. Johnson also stabbed Bratcher in the head with a screwdriver. After committing the murders, he hid the bodies in the store's bathroom and cooler before leaving the scene. He got rid of many of his belongings in a nearby field.

Johnson was arrested and went to trial in May 1995. The jury found him guilty on three counts of first-degree murder. They recommended that he receive the death penalty.

After some years, in 2008, Johnson underwent surgery to remove a brain tumor. Although the surgery was not entirely successful, it caused him to develop seizures. Johnson was worried that lethal injection would be painful for him. He requested to be executed by firing squad, but this was denied since Missouri did not allow it.

As the date of his execution approached, many people, including political and religious leaders, petitioned for clemency on his behalf. However, the requests were not granted. On October 5, 2021, Johnson was executed by lethal injection. He made a last statement, apologizing for his actions and thanking those who had prayed for him. The execution began, and he was pronounced dead nine minutes later. Before his execution, Johnson had a last meal consisting of two double bacon cheeseburgers, onion rings, two large strawberry milkshakes, and a large pizza.