Walt Stack (1908 – January 19, 1995) was an American long-distance runner and ultramarathon pioneer, known for his dedication to running in old age. Born in San Francisco, he worked as a sailor and construction worker before taking up running at age 50. He became an early advocate of ultrarunning, completing the Western States 100-mile race multiple times and over 100 marathons, including Boston. He continued running daily into his 80s, inspiring many with his motto: 'Start running, never stop.' His story symbolizes the power of endurance regardless of age.
