MacGregor played the general store owner's wife on all nine seasons of Little House on the Prairie, from 1974 until 1983.
Prior to her role on the show, she performed in productions of The Seven Year Itch and Handful of Fire, and landed roles on shows like Love of Life, East Side/West Side and All in the Family. Following Little House on the Prairie, MacGregor returned to primarily performing in local theatre productions.
See some of the social media tributes from her colleagues and fans below.
I just got word that Katherine MacGregor passed away yesterday. This woman taught me so much... about acting... vintage jewelry... life. She was outspoken and hilariously funny. A truly gifted actress as she was able to play a despicable character but with so much heart. Her Harriet Oleson was the woman our fans loved to hate. A perfect antagonist. The thing people outside of our prairie family didn't know, was how loving and nurturing she was with the younger cast. I really loved her and I find great comfort knowing that she is at peace and, per her beliefs, her soul has moved on to its next incarnation. Farewell Scottie. I hope with all my heart we meet again next time.
😢 She was deliciously wicked in Little House. Condolences to her family. https://t.co/TVWjY93Fpa— William Shatner (@WilliamShatner) November 14, 2018
Very sad to hear about the passing of Katherine MacGregor, aka Harriet Olson... She will be missed by the entire LHOTP family... thoughts go out to her loved ones and especially @Arngrim and @MEGBusfield... 🙏🏻💔 pic.twitter.com/cZCaMv2r8p— Melanie Landon (@melanielandon96) November 14, 2018