Waltons Star Mariclare Costello Passes Away at 90

Mariclare Costello, an actress celebrated for her role on "The Waltons" and in the cult film "Let's Scare Jessica to Death," died on April 17, 2026, in Brooklyn, N.Y., at age 90. Her family memorialized her as a person of rare gifts, who inspired creativity and paid close attention to the world around her.

Costello brought the character of Rosemary Hunter to life in the early seasons of "The Waltons." She shared fond memories of laughter and camaraderie with co-stars Richard Thomas and John Ritter during her time on the beloved series.

Originally from Peoria, Illinois, Costello pursued theater in New York City after earning a master's degree in theater and education. Her stage career included performances on Broadway and alongside notable actors like Jason Robards and Jimmy Stewart.

Transitioning to film and television in Los Angeles, Costello also appeared in "The Execution of Private Slovik" and series such as "Kojak" and "Murder, She Wrote." Her impact extended beyond performance, significantly influencing students as a drama teacher and director.

She was married to actor Allan Arbus until his death in 2013. Costello is survived by her daughter, Arin; granddaughter, Bird; stepdaughters, Amy and Doon; and nieces and nephews. Services are planned in New York City and Peoria.