ER

*ER* premiered on NBC on September 19, 1994, and ended on April 2, 2009, after 15 seasons. Created by Michael Crichton, who drew on his medical training, the drama follows the staff of County General Hospital’s emergency department in Chicago. Its stories move between incoming patients, treatment rooms and the doctors’ and nurses’ lives outside the hospital.

The original principal cast included Anthony Edwards as Dr. Mark Greene, George Clooney as pediatrician Dr. Doug Ross, Eriq La Salle as surgeon Dr. Peter Benton, Sherry Stringfield as Dr. Susan Lewis, Noah Wyle as medical student John Carter, and Julianna Margulies as nurse Carol Hathaway. Their roles changed substantially over the series. Carter progressed from student to physician; Ross left Chicago, and Hathaway later joined him in Seattle. Greene’s death from a brain tumor in the eighth season became one of the show’s defining departures.

*ER* rarely kept its ensemble static. Laura Innes joined as Dr. Kerry Weaver, whose authority in the department often put her at odds with colleagues. Gloria Reuben played physician assistant Jeanie Boulet, whose HIV diagnosis became an extended storyline. Later additions included Goran Višnjić as Dr. Luka Kovač and Maura Tierney as Dr. Abby Lockhart. The deaths of medical student Lucy Knight and Greene showed how the series could make the loss of a colleague central to its continuing story rather than confining it to a single case.

The production also made unusually conspicuous choices for a network drama. Quentin Tarantino directed the first-season episode “Motherhood.” “Ambush,” the fourth-season premiere, aired live in 1997, with separate performances for East and West Coast broadcasts. Alongside those experiments, the series used long, moving shots and crowded emergency-room scenes to follow several treatments at once.

*ER* won the Primetime Emmy Award for Outstanding Drama Series in 1996. Its success made Clooney a television star before his major film career, while Wyle’s long tenure as Carter provided a link between the original cast and later generations of County General staff. The finale, “And in the End...,” brought Carter back and introduced Greene’s daughter Rachel as a prospective medical student. It closed not with the emergency department empty, but with its staff responding to another arrival—a final scene rooted in the hospital’s continuing work.