Katharine Houghton was born on March 10, 1945, in Hartford, Connecticut, to Marion Hepburn Grant, Katharine Hepburn's younger sister, and Ellsworth Grant. Prior to pursuing a career in film, she attended Sarah Lawrence College, where she majored in philosophy. Her inaugural film appearance was in 1967's Guess Who's Coming to Dinner, where she played the role of Joanna Drayton alongside her aunt Katharine Hepburn, Spencer Tracy, and Sidney Poitier. Since then, Katharine has made over fifty stage appearances, including on and off Broadway productions, as well as regional theater performances in New England.
In addition to her acting credits, Katharine is a playwright, with a notable body of work that includes productions such as Best Kept Secret, Merlin, The Marry Month of May, Mortal Friends, On the Shady Side, The Right Number, Phone Play, and her translation of Anouilh's Antigone. Furthermore, Katharine presents lectures, having delivered talks titled Katharine X Three, My Grandmother's House Near the River, and The Secret Life of Louisa May Alcott.