Koepcke was born in Lima, Peru, in 1954 to German parents who worked at the Museum of Natural History, Lima. She was the only child of biologist Hans-Wilhelm Koepcke and ornithologist Maria Koepcke. When Koepcke was fourteen, her parents left Lima to establish Panguana, a research station in the Amazon rainforest. She became a “jungle child” and learned survival techniques. Educational authorities disapproved and Koepcke was forced to return to the Deutsche Schule Lima Alexander von Humboldt to take her examinations. She graduated on 23 December 1971.

Twenty-five years later, director Werner Herzog revisited the story in his film Wings of Hope (1998). In 1971, while location scouting for Aguirre, the Wrath of God, ironically, Herzog would have been on the same flight as Koepcke, but for a last-minute change of his itinerary. Koepcke accompanied him on a visit to the crash site, a journey she described as “a kind of therapy” for her.

After recovering from her injuries, Koepcke assisted search parties in locating the crash site and recovering the bodies of victims. Her mother’s body was discovered on 12 January 1972.

She moved to Germany, where she fully recovered from her injuries. Like her parents, she studied biology at the University of Kiel and graduated in 1980. She received a doctorate from Ludwig Maximilian University of Munich and returned to Peru to conduct research in mammalogy, specializing in bats. Koepcke published her thesis, Ecological study of a bat colony in the tropical rain forest of Peru, in 1987.

Now known as Juliane Diller, she serves as librarian at the Bavarian State Collection of Zoology in Munich. Her autobiography, When I Fell From the Sky (German: Als ich vom Himmel fiel), was released on 10 March 2011 by Piper Verlag, for which she received the Corine Literature Prize in 2011. In 2019, the government of Peru awarded her the Order of Merit for Distinguished Services, in the degree of Grand Officer.