Guardian of the Wilderness is a 1976 theatrical narrative film (often alternatively titled Mountain Man) directed by David O'Malley about the true story of Galen Clark, an explorer who successfully campaigned to have the Yosemite area set aside from commercial development, the original forerunner of the American national parks system.

[1] Clark was prompted by his dedication to preserving places like the Mariposa Grove of Giant Sequoias, which he discovered, from being destroyed by loggers.

Clark was eventually appointed Superintendent of Yosemite, a position in which he served for more than two decades during which he defined the concept of an American park ranger; his varied history with the valley ranged across 55 years.

The film was rated "G" and thereby deemed suitable for children, and was shot on location by cinematographer Henning Schellerup, edited by Sharron Miller, and released in the United States in December 1976 with a running time of 112 minutes.

Denver Pyle as Galen Clark Ken Berry as Zachary Moore John Dehner as John Muir Cheryl Miller as Kathleen Clark Ford Rainey as Abraham Lincoln Norman Fell as Doctor Cliff Osmond as McCollough Jack Kruschen as Madden Don Shanks as Teneiya[6] Melissa Jones as Heather Brett Palmer as Joey Prestiss Rowe as Forbes Hyde Clayton as Chairman of Legislature Coleman Creel as Senator John Conness Michael G. Kavanagh as General Carson Tom Carlin as Harold Lawson Earl Benton as President's secretary Michael Ruud as Officer Lynn Lehman as State Representative Galen Clark John Muir John Conness Mariposa Grove Giant sequoias Yosemite National Park National Park Service