Season 1 of Grey's Anatomy was filmed primarily throughout . While a specific calendar date for the "first day of filming" is not publicly documented in standard production archives, several key milestones from its production cycle confirm this timeframe.
There is a famous story about the first day on set. Sandra Oh, who had primarily done indie films, filmed her very first scene and immediately thought she had ruined her career. She went to the producers, terrified, convinced she couldn't act for television. She asked to be let out of her contract so she could return to doing theater in New York. The producers, realizing the magnetic energy she brought to the character, refused. They told her to trust the process. It was a good thing they did—Oh would go on to become the emotional anchor of the show. when was season 1 grey's anatomy filmed