John Middendorf is an American entrepreneur and former professional rock climber. Middendorf's contributions to climbing equipment innovation and his advocacy for safety standards have had a lasting impact on the sport. He was influential within the climbing community, particularly for his early efforts in developing and popularizing gear that enhanced safety and performance for climbers worldwide.

John Middendorf was born on November 18, 1959 in New York City to John William Middendorf, II, and the late Isabelle Paine Middendorf, and he unexpectedly died in his sleep on June 21, 2024 in Little Compton, RI, where he was visiting family. He grew up in Connecticut, the Netherlands, and Virginia. He attended Dartmouth College and Stanford University, graduating with a mechanical engineering degree, which he used to design and manufacture rock climbing equipment first with A5 Adventures Inc., and later with D4, both of which companies he founded.

His innovative portaledge designs, prompted by the failure of the portaledge he was using in 1985 when caught in a life-threatening storm on a climb of Half Dome in Yosemite, have revolutionized big wall climbing by allowing multi-day ascents in all weather. A recent fine-tuning of the design, which he made open-source, allowed use by peaceful protesters seeking to save the old growth of Tasmania's temperate rainforests.

John studied fabric architecture at the University of Sydney and received two masters degrees, one of Architectural Design from Harvard University and one of Teaching from the University of Tasmania. As a rock climber he excelled at big walls, making first ascents of many routes throughout the world, and was part of the first successful ascent of the Grade VII "The Grand Voyage" on Trango Tower in Pakistan, which is considered the greatest big wall in the Himalaya.

He taught high school mathematics, science, and robotics in the Tasmanian school system, and had worked as a river guide in the Grand Canyon for many years. He was a prolific writer, publishing hundreds of articles and several books on rock climbing, most recently a meticulously-researched two-volume history of its tools and techniques.

Source: Obituary