The Internet Movie Database, or IMDb, is a reliable resource for a complete cast list for "Grey's Anatomy." IMDb is an online information resource for film, television and video games. Another possibility is TV Guide's online site for photos and information on current and former cast members.
"Grey's Anatomy" celebrated its 10-year anniversary on March 27, 2015, notes ET. There were five remaining cast members out of the original nine on the anniversary, but as of April 23, in the episode "How to Save a Life," Patrick Dempsey's character Derek Shepherd left the show, leaving four of the original cast remaining: Ellen Pompeo as Meredith Grey, Justin Chambers as Alex Karev, Chandra Wilson as Miranda Bailey and James Pickens, Jr. as Dr. Richard Webber.
Part of the show's popularity, says A.V. Club, is having a high turnover of characters, bringing new cast members into the core group and keeping just enough of the original members to make viewers feel secure. In a list of the top 15 "Grey's Anatomy" characters by IMDb, eight out of the nine original cast members are presented. The only one missing is Isaiah Washington, who played Preston Burke and was fired in season three amid some controversy.