George O’Malley dies in Grey’s Anatomy in season 6, in the first episode of that season titled “Good Mourning.” He is struck by a bus while saving a woman, his condition worsens during surgery and he ultimately dies from brain swelling, after his true identity is revealed as the John Doe patient. Key points:

• Episode: Good Mourning (Season 6, Episode 1)
• Cause: Injuries from being hit by a bus; brain swelling during or after surgery
• Impact: George’s death profoundly affects his friends and colleagues, and the show later reveals the organ donation decisions surrounding his death.