Johan Reinhard began his anthropological field research in Nepal, where his studies over ten years included shamanism, sacred mountains of Tibetan Buddhism, and culture change among one of the world's last nomadic hunting and gathering tribes. His work in the Andes has focused on sacred landscape beliefs among mountain peoples, including investigations of Inca ceremonial sites on mountain summits, the Nasca Lines, and the ancient ceremonial centers of Machu Picchu, Chavin, and Tiahuanaco.

In the late 1980s, Reinhard directed the first underwater archaeological project in Lake Titicaca. In later research he recovered the Inca ice maiden mummy on Peru's Mount Ampato, a discovery chosen by Time magazine as one of the world's ten most important scientific discoveries of 1995. His expeditions in the Andes have led to the discovery of over a dozen Inca human sacrifices on five mountains, including three remarkably preserved mummies on Argentina's Mount Llullaillaco, the world's highest archaeological site (22,100 feet).

Museums have been built in three countries to exhibit the archeological finds made during his expeditions. Reinhard has authored more than 70 publications, including six books, and his research has been featured in a number of TV documentaries. His work has been distinguished with several awards, including the Rolex Award for Enterprise, the Puma de Oro (Bolivia's highest award in the field of archaeology), and the Explorers Medal of the Explorers Club, while Outside magazine selected him as one of today’s 25 most extraordinary explorers. His book  Ice Maiden:Inca ice maiden mummy was published in 2005 by National Geographic and UCLA has published his latest books Machu Picchu: Exploring an Ancient Sacred Center (2007) and Inca Rituals and Sacred Mountains: A Study of the World's Highest Archaeological Sites (2010).