From its captivating debut in September 1994 to its emotional farewell in 2009, “ER” dominated television, becoming a cultural phenomenon. With 331 episodes, this medical drama was not just a ratings giant; it launched numerous careers and featured a myriad of guest stars who later became household names. Think George Clooney, Anthony Edwards, Maura Tierney, and Eriq LaSalle among the regulars, and a revolving door of notable cameos that added spice to the show.