Nothing is known about Percy's life before the outbreak or as the outbreak began. It is possible that he lived in or near Atlanta.
Percy is seen standing outside his room, participating in a plan that he and Beth Greene made to create a distraction. After he receives some strawberries from Beth, he fakes a sudden and severe coughing fit. As Beth sneaks off to the hospital's medicine cabinet to retrieve some epinephrine for Carol Peletier, a new patient at the hospital who happens to have been part of Beth's previous group, Percy continues to cough, distracting Officers Alvarado and Tanaka. When Beth walks by, as a sign of mission complete, Percy stops coughing and alerts the officers that he is fine.
Percy is harassed by Officer O'Donnell but is saved from harm after Dawn Lerner tells O'Donnell to back off. After the deaths of Beth and Dawn during the unsuccessful hostage exchange, Rick Grimes lets the patients know that they can leave the hospital with his group if they wish. However, Percy, Dr. Steven Edwards, and the other patients choose to stay.
This list shows the victims Percy has killed:
- Possibly numerous counts of zombies
- Percy was credited for "Slabtown" but the scene was deleted.
- In a deleted scene for "Coda", Percy is critically injured after O'Donnell shoves him down. He refuses help from Dr. Edwards but Beth tells him that he should get the help. Dawn ultimately tells Dr. Edwards to help him.