George O'Malley, played by T.R. Knight, left Grey's Anatomy due to a combination of behind-the-scenes issues, including a breakdown in communication with the show's creator Shonda Rhimes, discomfort with how his character's storylines were being handled, and the negative atmosphere following alleged homophobic comments from co-star Isaiah Washington. Knight was also unhappy with George's character development, especially after a controversial cheating storyline, and felt underutilized with reduced screen time. Ultimately, Knight chose to leave the show in 2009, leading to his character's dramatic death in season 6 by complications from an accident after saving a woman from a bus. Knight has expressed that moving on was the best decision for him despite the challenges he faced on the show and has since returned briefly for a guest appearance in season 17.