Katherine MacGregor. Actress: Little House on the Prairie. Best known for her performance as the nasty, gossiping, greedy and arrogant Mrs. Harriet Oleson on the TV series Little House on the Prairie (1974). Katherine (Scottie) MacGregor could not appear in the final feature length episode "The Last Farewell" because she was on a pilgrimage in India. Before moving to Los Angeles in 1970 Ms. Mac Gregor worked as a stage actress...