Christopher Sepulvado was born on November 11, 1943, in Louisiana, United States. Little is publicly documented about his early life, upbringing, or education. His life gained public attention in the early 1990s when he entered a relationship with Yvonne Mercer, a woman with a young son named Wesley. Sepulvado and Yvonne began living together in Mansfield, Louisiana, in January 1991, despite objections from her family. Sepulvado married Yvonne Mercer on March 5, 1992.

On March 8, 1992, Christopher Sepulvado killed his six-year-old stepson, Wesley Allen Mercer, in Mansfield, Louisiana. This tragic event resulted from severe abuse inflicted upon the boy. Three days before the murder, on March 5, 1992, Sepulvado had married Wesley's mother, Yvonne Mercer. The abuse started soon after.

On March 6, 1992, Wesley returned home from school and had multiple accidents in his pants. His mother punished him by not allowing him to eat and spanked him. Sepulvado escalated the abuse by threatening to hang Wesley and using a belt to whip him. He also forced Wesley into a toilet bowl. On March 7, Sepulvado ordered Yvonne not to feed Wesley, leading to the boy being starved and mistreated further.

On the morning of March 8, 1992, the abuse culminated in a horrific act. Sepulvado kicked Wesley into the bathroom and threatened to scald him with hot water. When Wesley hesitated to dress for church, Sepulvado hit him repeatedly on the head with a screwdriver until Wesley lost consciousness. After this, Sepulvado placed him into a bathtub filled with scalding water. After the attack, Wesley vomited and fell over, leading to his loss of consciousness.

Three hours later, Sepulvado and Yvonne took Wesley to DeSoto General Hospital, but he was pronounced dead shortly after arrival. An autopsy revealed that Wesley had suffered severe burns covering 58% of his body and multiple head injuries.

Following the police investigation, both Sepulvado and Yvonne were arrested. Sepulvado was charged with first-degree murder, while Yvonne faced a second-degree murder charge. Sepulvado admitted to assaulting Wesley but claimed that the boy accidentally fell into the water. In April 1993, a jury convicted Sepulvado of first-degree murder and recommended the death penalty.

Sepulvado was sentenced to death on May 24, 1993. Yvonne received a lesser sentence of 21 years and was released in 2002 after serving part of her sentence. Sepulvado's appeals continued for years but were consistently denied, including by the Louisiana and U.S. Supreme Courts.

After numerous legal battles, a death warrant was issued for Sepulvado, with his execution initially scheduled for February 13, 2013. This was delayed multiple times due to legal challenges regarding the state’s lethal injection methods.

On February 12, 2025, a death warrant was signed for Sepulvado, scheduling his execution for March 17, 2025, by nitrogen hypoxia. At 81, Sepulvado was in poor health and confined to a wheelchair. His legal team argued for clemency on compassionate grounds, but his death sentence remained in place.

However, before the execution could occur, Sepulvado died of natural causes on February 22, 2025.