The 77-year-old actress passed away on Monday (12Oct20) at Sherman Oaks Hospital in California.
Ferrell, who portrayed housekeeper Berta on TV for 12 years, earning two Emmy nominations, also appeared on "L.A. Law", "Good Times", "E/R", "Grace and Frankie", and "Buffy the Vampire Slayer".
An original member of the Circle Repertory Theatre, she enjoyed huge successes onstage too, appearing in "The Sea Horse" in 1974, for which she earned Drama Desk, Theatre World and Obie awards for Best Actress, "Hot L Baltimore", "Battle of Angels", and "Picnic".
Meanwhile, her film credits include "Network", "Mystic Pizza", "True Romance", "Erin Brockovich", and "Edward Scissorhands".
Born in Charleston, West Virginia, Ferrell graduated from Marshall University with a degree in history education. She later taught acting for television at UCLA.
Her most recent acting credits have included Netflix's "The Ranch" and TV movie "A Very Nutty Christmas".
Ferrell was admitted to a long-term care facility after suffering a heart attack over the summer. She battled a variety of health issues ever since she was hospitalised with a kidney infection in West Virginia in December (19).
She spent much of January recuperating at her home in Charleston, where she also underwent physical therapy, but she was hospitalised again in May (20) as she struggled to overcome an illness linked to her prior infection.
Her husband Arnie previously said of her health issues, "It's all neurological. There's nothing we can do to speed it up the process. We are hoping for the best."