Billy "Bill" Callahan is an Irish man who came to Sacred Heart Hospital to visit a patient that he hospitalized.
Billy Callahan is originally from Ireland but spent an unknown amount of time in the US. He enjoys embracing life by living every day doing something fun rather than staying in and doing less. However, this caused a problem when he went out to enjoy life at a bar, but got drunk and then had a bar fight, injuring the other person. However, when that person was admitted to Sacred Heart, Billy came to the hospital too and stayed by him, hoping to stay until the other man recovered. However, J.D. and Turk were not allowed by hospital policy to let Billy stay, and they also had the responsibility to report him to the police - which they did, and he was arrested. A short while later, he is released and returns to the hospital to apologize to the patient he punched, who is now recovering, and the patient admits to throwing the first punch and they are both fine with each other. J.D. apologizes to Billy for calling the police, who forgives him but questions why J.D. didn't just speak to him first, and J.D. and Turk then realize that they were jealous of Billy's exciting life. Now that he has apologized to the patient from the bar, Billy decides to leave the hospital, to all the female staff's (& Todd) sadness. ("My Lucky Charm")
J.D. and Turk called the police on Billy after he told them that he was the one who hospitalized their patient, and caused Billy to be arrested. When he was released and returned to the hospital, he forgave them after they apologized but questioned why they didn't speak to him about it first - and they then realized they were jealous of Billy's way of living life to the full.
Billy and the Bar-fight patient met at a bar near Sacred Heart Hospital and due to alcohol and anger, they got into a fight which ended in Billy punching in the face and hospitalizing the bar-fight patient. However, Billy sat by the bar-fight patient's bed while he recovered, waiting for him to finally wake up, and when he did wake up Billy apologized and the two both forgave each other after the bar-fight patient admitted to throwing the first punch.
Female Staff of Sacred Heart (& Todd)
All the female staff at Sacred Heart loved Billy because he was Irish, hot and charming - and they all got very angry at J.D. and Turk when they got him arrested. Todd admitted to also finding Billy attractive because he "appreciates hot regardless of gender". Billy also went around chatting up some of the female staff (most notably Elliot and Carla) before starting to passionately kiss, and this would usually occur within 10 seconds of meeting Elliot & Carla.
- Embracing life
- Wasting his life
- Going Outside