Keeshan died in Windsor, Vermont, on January 23, 2004, at age 76. He was survived by three children: Michael Derek, Laurie Margaret, and Maeve Jeanne. His wife of 45 years, Anne Jeanne Laurie Keeshan, died February 25, 1996. Keeshan's grandson, Britton Keeshan, became the youngest person at that time to have climbed the Seven Summits by climbing Mount Everest in May 2004. He carried photographs of his grandfather on that ascent, and buried a photo of the two of them at the summit.