George O'Malley was the son of Harold and Louise O'Malley. He started work at Seattle Grace Hospital and after a bad start, he became one of the best with a great interest in trauma. Fellow resident Izzie Stevens became his best friend and for a while he was married to Callie Torres. He was kind-hearted, compassionate, loyal and had an excellent bedside manner. He died in surgery shortly after jumping in front of a bus to save a woman's life.

Since his birth, George was soft and emotional. He represents the good and polite child in the family. During his early years (up until adulthood) he spent his time camping with his father and his brothers hunting turkeys, although George refused every single year. George was often teased by his brothers due to his lack of manhood. He and his brothers were taught about cars and other "guy's stuff". Despite this he was growing up, competing with his brothers and always trying to the right thing.

He was also very emotionally attached to his dog Bucky, whom he thought had run away, not knowing that his father accidentally ran over and killed the dog, which was chasing after the truck and got caught under the tire. His father knowing that George would be devastated, lied to him, telling him that Bucky had escaped.