Maria O’Brien Dies: ‘Protocol’ & ‘Matlock’ Actress Was 75

Michelle Stein March 4, 2026, 8:36 am

What To Know

Maria O’Brien, known for roles in Protocol and Matlock, died on February 24 at 75.
She had a six-decade career as both an actress and acting coach, working on soaps like Days of Our Lives and appearing in numerous TV shows and films.
O’Brien came from a family of actors, including Oscar-winning father Edmond O’Brien, actress mother Olga San Juan, and late brother Brendan O’Brien.

Maria O’Brien, the actress best known for her roles in Protocol and Matlock, is dead at 75.

On February 24, O’Brien died—although her cause of death was not publicly shared—multiple outlets, including The Hollywood Reporter and Variety, reported.

O’Brien started her career as an acting coach, working on the sets of soap operas such as Passions and Sunset Beach. She also served as an acting coach for Days of Our Lives for 15 years until retiring in 2022.

In 1984, O’Brien played a character named Nancy in the film Protocol. And in 1988, she played Juanita Martinez in Matlock. She also had acting credits in films like The Incredible Shrinking Woman (1981) and Table for Five (1983). TV-wise, she appeared in many guest roles through her six-decade career, including: Magnum P.I., Murder, She Wrote, The Love Boat, LA Law, CHiPs, Jack & Jill, Spyder Games, For the People, and more.

O’Brien was born into a family of actors, including her father, Edmond O’Brien, who won the Oscar for Best Supporting Actor in The Barefoot Contessa (1954). Meanwhile, her mother, Olga San Juan, appeared in films like The Countess of Monte Cristo, Are You with It?, and One Touch of Venus. After her father was diagnosed with Alzheimer’s, O’Brien testified to Congress in 1983 about the impact of the disease. (Edmond died in 1985.)

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Her brother, Brendan O’Brien, was also an actor who voiced the titular character (and others) in the video game franchise Crash Bandicoot. His other credits included the film Totally Killer in 2023, an episode of Riverdale in 2021, six episodes of the TV series Spawn, and more.

O’Brien is survived by three children, James Anderson, Danica Anderson, and Sean Anderson; and her sister, Bridget O’Brien Adelman. She was preceded in death by her brother, Brendan, and her parents.