|Affiliation:||Counter Terrorist Unit|
|Profession:||Field agent, CTU Los Angeles|
|Died:||Day 4: 4:58am|
Shot by Mandy
|Played by:||Cameron Bancroft|
Before Day 4
Agent Castle was called in with a TAC team to capture Dina Araz and her son Behrooz. He was initially concerned when Jack Bauer insisted that civilian Tony Almeida assist in the operation, and became outwardly angry when Tony restrained him from unwisely torturing Dina in a fit of rage after her apprehension.
Castle responded with Jack and another team of agents at the Rockland Building, where Habib Marwan and one of his cells were operating the Dobson Override. When Marwan's sleeper agent at IDS Data Systems, Ali, moved to fire on the agents, Castle killed him.
Agent Castle then led the TAC team to the ammunition store owned by civilians Safa and Naji, where Jack and Paul Raines defended themselves with the two brothers against private McLennen-Forster commandos hired by Dave Conlon. During the rescue misson, Castle shot Conlon in the back; the wound was not instantly fatal, and Conlon survived for a few more moments to shoot Paul.
Lee, while functioning as a counter-sniper during a hostage exchange, saved Jack's life by taking out Marwan's sniper, who had Jack in his crosshairs.
During his next mission, Lee participated in the raid on one of Marwan's satellite bases. Though Marwan escaped this raid, a number of his conspirators were killed (chief among them Rafique).
He also participated in the raid at The Mercerwood to capture Mandy and Gary, two of Marwan's mercenaries. There, minutes before 5:00 AM, he was shot in the shoulder and foot by Mandy. After she instructed him to handcuff Tony Almeida so she should take him as a hostage, she shot and killed him.
- Lee Castle: Hey, Jack. Good to have you in the field again.
- Jack Bauer: Thanks, Lee. You remember Tony Almeida?
- Lee Castle: Yeah. I don't know what he's doing here, though.
- Jack Bauer: I want him here.
- Lee Castle: He's not authorized to be in the field.