Mariclare Catherine Costello (February 3, 1936 – April 17, 2026) was an American actress. She was a lifetime member of The Actors Studio. Costello's most notable role was that of Rosemary Hunter Fordwick on the television series The Waltons, from 1972 to 1977. In 1977, after her role on The Waltons, she played matriarch Maggie Fitzpatrick on the short-lived drama show The Fitzpatricks.
2000Shadow of the Blair WitchMovieas Kathy Patterson1994Chicago HopeTV showas Mother Mary Catherine · 1 episodes1993Indecent ProposalMovieas David's Mother
1990She Said NoMovieas Susan Finn
1990AppearancesMovieas Rose
1987American HarvestMovieas Mary Alice Duncan1985Heart of a Champion: The Ray Mancini StoryMovieas Ellen Mancini1984Victims for Victims: The Theresa Saldana StoryMovieas Jane Bladow1984Murder, She WroteTV showas Cassie Latham Burns · 1 episodes1984The Adventures of Buckaroo Banzai Across the 8th DimensionMovieas Senator Cunningham1983NightmaresMovieas Adele Cooney (segment "The Bishop of Battle")
1982SkeezerMovieas Barbara Thompson1981Coward of the CountyMovieas Emma Spencer1980Ordinary PeopleMovieas Audrey
1980All God's ChildrenMovieas Winnie Naponic
1980The Boy Who Drank Too MuchMovieas Louise Carpenter1979Hart to HartTV showas Anita Boyer · 1 episodes1977The Incredible HulkTV showas Kay Wallace · 1 episodes1977Lou GrantTV showas Louise Larsen · 1 episodes
1977The FitzpatricksTV showas Maggie Fitzpatrick · 13 episodes
1977A Sensitive, Passionate ManMovieas Pat Morris1976Raid on EntebbeMovieas Gabrielle Krieger
1976Territorial MenMovieas Julia Baker
1975Conspiracy of TerrorMovieas Mrs. Warnall
1974After the FallMovieas Louise1974The GunMovieas Beryl Strauss1974The Execution of Private SlovikMovieas Antoinette Slovik1973KojakTV showas Diane Gordon · 1 episodes
1972Going Where I've Never Been: The Photography of Diane ArbusMovieas Herself - Narrator1972The WaltonsTV showas Mrs. Rosemary Fordwick · as Miss Rosemary Hunter · as Mrs. Rosemary Fordwick (archive footage) · 4 episodes1971Let's Scare Jessica to DeathMovieas Emily1970PoundMovieas Honky Killer's Wife