O'Donnell is a supporting antagonist in the AMC series The Walking Dead.
He is a survivor of the zombie apocalypse who took refuge in the Grady Memorial hospital and along with his companions sheltered patients and refugees there.
He was portrayed by Ricky Wayne.
O 'Donnell was a family man who after meeting with the Police Academy met officer Dawn Lerner with whom he worked and eventually made a good friendship. After losing his family, along with Dawn and other officials they kept shelter in the hospital. Although, probably because of the loneliness of his family and his responsibility, the officer began to change drastically, with a more violent and apathetic personality, and Lerner did not do anything about it (previously the leadership of the hospital was headed by a captain named Hanson, whom Dawn killed for his lack of responsibility). O 'Donnell had a fellow friend in the hospital called Gorman who after losing his sanity began to abuse and rape patients, being the most noticed Joan, and also Beth Greene, while O' Donnell laughed at it. When he and another officer accidentally ran over Carol Peletier, the man did not bother to save her, and even suggested that he be disconnected from his equipment, to the annoyance of Beth, who already had a grudge against him. O 'Donnell, like Gorman, lost his sanity and began to have corrupt and almost deranged tendencies, for example when he struck and intimidated an old man by badly sewing his uniform. This was seen by Beth who accused O Donnell Dawn's likely best friend of doing nothing about it. After hearing the conversation, a fight ensued between O 'Donnell and Lerner with witness Beth. Although the officer was winning, the man reduced it and tried to strangle against a wall, which caused Beth to try to intervene for her protector, but the officer hits her. Taking advantage of the distraction, Dawn returned to take the reins of the fight and after hitting it in the throat and to kick it in the stomach, gave the order to him to finish it, pushing it to the shaft of an elevator, dying at the moment, and its body was devoured by walkers from the bottom of the elevator.
- He had a violent, manipulative and abusive character, but according to Lerner it was not like that.
- It is known that he had a wife and a son but nothing more.
- Except for Dawn and Alvarado, he is not seen interacting with any other officer.
- It was Dawn's right hand.
- Except Beth and to a lesser extent Carol, does not share plot with any other main personage.
- It is unknown whether he revived as a walker in the elevator or not.