"A Hard Day's Night" is the pilot episode and series premiere of the American television medical drama Grey's Anatomy, which first aired on March 27, 2005 on ABC.

The episode introduces the main characters and surgical interns Meredith Grey (Ellen Pompeo), Cristina Yang (Sandra Oh), Izzie Stevens (Katherine Heigl), George O'Malley (T. R. Knight), and Alex Karev (Justin Chambers), as they begin their journey into the world of surgery at Seattle Grace Hospital.

Other key characters introduced in the episode include Derek Shepherd (Patrick Dempsey), Miranda Bailey (Chandra Wilson), Richard Webber (James Pickens Jr.) and Preston Burke (Isaiah Washington).

The episode opens with a voice-over narration from Meredith Grey (Ellen Pompeo) about embracing challenges and uncertainty by finding passion in your chosen path.

Meredith Grey (Ellen Pompeo) is shocked to discover that Derek Shepherd (Patrick Dempsey), with whom she had a one-night stand the night before, is not only an attending physician but also the Chief of Neurosurgery.

[6] Meredith struggles with her first case, involving a teenage pageant contestant named Katie Bryce (Skyler Shaye), who suffers from unexplained seizures.

"[12] However, Rhimes raised concerns to writer Eric Buchman about the title Complications because Atul Gawande had written a book by the same name, which also revolved around a "young doctor working for a hospital for the first time".

"[12] The character of Preston Burke was initially conceived as Caucasian and intended to be played by Paul Adelstein, who would later star in Grey's Anatomy's spin-off, Private Practice.

[1][2] ReviewStream.com gave positive feedback on the pilot episode of Grey's Anatomy, particularly highlighting the undeniable chemistry between Ellen Pompeo and Patrick Dempsey from their very first scene.

"[2] On the other hand, HomeTheaterInfo.com provided mixed-to-positive perspectives, acknowledging that the storylines bore similarities to the fellow ABC series Desperate Housewives, but also calling the pilot "brilliantly written, extremely well acted, and directed to near perfection.

"[18] The New York Daily News named Grey's Anatomy a "winner" following its first season, while Newsday expressed a similarly positive opinion, stating, "You simply can't stop watching.