Schmitt grew up in Berkeley, California, the son of mixed German and American parentage. His father was a plumber. He showed early aptitude with languages, music and mathematics, and went on to study linguistics with Noam Chomsky in his late teens. Chomsky recruited Schmitt, aged 19, to travel to Alaska's Brooks Range and attempt to learn the Nunamiut dialect.
Schmitt speaks ten languages, including Russian, Norwegian, Danish, and French. Schmitt lived for four years at an Alaskan Eskimo village named Anaktuvuk Pass before leading expeditions, including the Sierra Club.
In 2003, Schmitt discovered one of the candidates of being the northernmost land in the world. Deciding that Greenland should name its own islands, he simply called it "83-42", a name that has remained.
Two years later, in 2005, Schmitt discovered a new island formed by the retreat of an ice shelf in East Greenland. Uunartoq Qeqertaq, Inuit for "The Warming Island", lies 400 miles north of the Arctic Circle. The Sierra Club reported on a Schmitt quote to the New York Times:
- "We felt the exhilaration of discovery. We were exploring something new. But of course, there was also something scary about what we did there. We were looking in the face of these changes, and all of us were thinking of the dire consequences."
Schmitt is also credited with the July 2007 discovery of another of the candidates to the "northernmost island on Earth"-title, named Stray Dog West by expedition member Holly Wenger. Stray Dog West, at 83º40'30", belongs to a shifting, semi-permanent archipelago locked in the sea ice north of Peary Land in northeast Greenland, named the Stray Dog Islands. The first island of the archipelago was discovered in 1996 by Dennis Schmitt and Bob Palais.
He is the first person to climb Alaska's Brooks Range from Point Hope to the Mackenzie River, and made the first traverse of Axel Heiberg Island, northern Canada. He also crossed the sea ice of the Bering Straits to the Soviet Union, and travelled through Eskimo villages of eastern Siberia. Upon his return, the FBI detained and released Schmitt without charge.
Schmitt lives in Berkeley. He composes classical music, being credited for the soundtrack to the 1978 movie, The Alaska Wilderness Adventure. Schmitt also writes sonnets under the pen name D O'Farrell.
- The World's Northernmost Point Is Called 83-42. Maybe. The Daily Traveller, February 16, 2012
- "Geography in Action". Sierra Club. 2007-06-05. Retrieved 2007-09-23.
- Richardson, John H. (2007-09-18). "Journey to the End of the Earth". Esquire Magazine. Retrieved 2007-09-23.
- Hansen, Kathryn (2007-09-18). "TRENDS & INNOVATIONS Ice Voted off Warming Island". Geotimes. Retrieved 2007-10-21.