William George Davis was born on February 3, 1984, in Longview, Texas. He grew up in a regular household in East Texas. Not much is publicly known about his early life or family.

Davis pursued a career in nursing after finishing school. He worked as a nurse at Christus Trinity Mother Frances Hospital in Tyler, Texas.

From 2017 to 2018, patients in a Texas hospital experienced serious complications after heart surgery. Doctors found air bubbles in the brains of these patients when they performed CT scans. Security footage revealed William George Davis in the patients' rooms just before their conditions worsened.

Davis was a nurse at the Christus Trinity Mother Frances Hospital in Tyler, Texas. He was fired from his job a month before his arrest in April 2018. He pled not guilty to the charges against him. His defense attorney suggested that Davis was being blamed for the deaths because he was present when they occurred.

On October 19, 2021, a jury found Davis guilty of capital murder for the deaths of four patients: John Lafferty, Ronald Clark, Christopher Greenaway, and Joseph Kalina. The first three patients died in 2017, while Kalina was attacked in 2018 and died two years later. During the trial, prosecutors argued that Davis had intentionally harmed the patients by injecting air into them. They played a recorded phone call from jail where Davis mentioned wanting to keep patients longer in the intensive care unit to earn more overtime pay.

On October 27, 2021, after a short deliberation, the jury sentenced Davis to death. He was also accused of causing the deaths of three other patients and injuring five more. Davis's sentence is automatically on appeal.