Jeanne Cooper, Actress in "Young and the Restless," Dies Sean Smith/Sony Pictures Television Jeanne Cooper, left, and Jess Walton in "The Young and the Restless" on CBS in 2011. Ms. Cooper took on the role in 1973. Jeanne Cooper, the enduring actress on "The Young and the Restless" who had much in common with her character, the forthright Katherine Chancellor - apart from everyday occurrences in the soap opera universe like being stranded on a desert island with nothing but her jewelry, having a shopping center fall on her and inadvertently giving one of her grandchildren away - died on Wednesday in Los Angeles. She was 84 and continued to appear on the show until her death. Her son, the actor Corbin Bernsen, announced the death on his Facebook page, writing that his mother had died in her sleep. Ms. Cooper was the longest-serving cast member of "The Young and the Restless," having joined the show in late 1973, about six months after CBS began broadcasting it. As Katherine Chancellor, she played the fabulously wealthy matriarch of fictitious Genoa City, Wis. "The Young and the Restless" is taped about six weeks in advance, and it has not been determined how Ms. Cooper's character will be written out of the show, a CBS spokeswoman said on Wednesday. Some of Katherine's travails on the soap opera were Ms. Cooper's own, including her alcoholism and subsequent sobriety, a journey she chronicled candidly in a memoir, "Not Young, Still Restless," written with Lindsay Harrison and published last year. When Ms. Cooper had a face-lift in 1984, it quickly became Katherine's face-lift, with footage of Ms. Cooper's actual surgery incorporated into the broadcast. The two women diverged in certain vital respects. Compared with the patrician Katherine, Ms. Cooper had a far more extensive Anglo-Saxon vocabulary, which she used with robust delight in interviews. Ms. Cooper was married and divorced only once, areas in which her on-screen alter ego - technically, though not necessarily in this order, Katherine Shepherd Reynolds Chancellor Thurston Sterling Murphy - set the bar extremely high. For her work on the show Ms. Cooper received two Emmy Awards: a lifetime achievement award in 2004, and a Daytime Emmy for outstanding lead actress in a drama series in 2008. She also made guest appearances on "L.A. Law," playing the mother of Mr. Bernsen's character, Arnie Becker. Wilma Jeanne Cooper was born in Taft, Calif., on Oct. 25, 1928. She studied acting at the Pasadena Playhouse and the College of the Pacific in Stockton, Calif. Her early film work included "The Redhead From Wyoming" (1953) and "The Man From the Alamo" (1953). She had guest parts on many TV shows, including "The Twilight Zone," "Gunsmoke," "Bonanza," "Perry Mason" and "Ironside." Ms. Cooper's marriage to Harry Bernsen, a producer, ended in divorce. Besides her son Corbin, her survivors include another son, Collin, also an actor; a daughter, Caren; and eight grandchildren, none of whom, according to any available source, she ever tried to give away.