Mariclare Costello, ‘The Waltons’ Actress, Passes at 90
on Apr 28, 2026
The Waltons Has Lost Another Family Member
Mariclare Costello, the actress beloved for her role in The Waltons TV series, has died. She was 90 years old.
According to her obituary published in the Peoria Journal Star and online, Costello passed away on Friday, April 17, 2026 in Brooklyn, New York.
Her death comes about a year after after the death of Sian Barbara Allen, and nearly two years after Tom Bower’s passing, both of whom starred on The Waltons.
Costello’s survivors include her daughter, Arin; Arin’s partner Ethan’ gradndaughter Bird; step-daughters, Amy and Doon; and beloved nieces, Moira, Elizabeth, Molly, Sarah, Kate and Julia, and nephew, Jim, and their families.
She was preceded in death by her husband, Allan Arbus; her sisters, Marjorie Klise and Joan McQuillen; and nephews, Matthew and Michael.
Her family remembers her as someone who “could talk to anyone, was interested in everything, and was a relentless asker of questions.”
They said, “Her gift was rare; she knew how to get people out of their own heads, focused on a task rather than on themselves, and in doing so helped them access their own creative voices.”
Mariclare Was A Veteran Of The Stage And Screen
After getting a degree at Clarke College, Costello received her masters degree in theater and education from Catholic University. While studying improv under Viola Spolin, she performed for President Kennedy.
She moved to New York City after graduation, where she found great success on stage. She was part of the original Lincoln Center Repertory Company, where she trained and worked alongside Jerome Robbins, Harold Clurman, Michel Saint-Denis, Jose Quintero, Hal Holbrook, Austin Pendleton, Faye Dunaway, Stacy Keach and James Earl Jones.
The actress was also a lifetime member of The Actor’s Studio.
Costello starred in several Broadway plays and acted opposite some legendary names including Jason Robards and Jimmy Stewart.
She met her husband, Alan Arbus, in an acting class and after doing a play together, they moved to Los Angeles. That’s when her film and TV career took off.
Her star was attached to the cult classic film Let’s Scare Jessica to Death, as well as The Execution of Private Slovik.
On television, she is known as the beloved teacher Rosemary Hunter on The Waltons from 1972 to 1977.
Following her acting career, she became an acting professor at Los Angeles’ Loyola Marymount University.
Her Beloved The Waltons Co-Star Pays Tribute
Judy Norton, who played Mary Ellen Walton on the award-winning drama series, took to social media to mourn Mariclare’s death.
“Such devastating news to hear of the passing of our beloved Mariclare Costello who graced our lives and screens for decades,” she wrote. “We were blessed with her presence as Miss Rosemary Hunter Fordwick for 5 seasons on The Waltons.”
Norton continued, “I have been trying to track her down for some time now in hopes of having her join me as a guest on my YouTube channel. I’m gathering together a tribute segment to honor her – I hope you’ll all help me to wish her Godspeed on her journey forward.”
See Norton’s post below.
