[1] Agathe was born on 12 March 1913 in Pola, Istria, then part of the Austro-Hungarian Empire (present-day Pula, Croatia).

[5] After the war, Agathe moved with her family to a house called "the Martinschlossl", in Klosterneuburg, a half hour train ride from Vienna, near the Danube.

[11] After graduating from high school, Agathe tutored briefly,[12] and then pursued her loves of painting, languages, and sewing.

[13] While they did this just for enjoyment at first, their hobby turned into a career for the von Trapps after much of their money was lost in the global depression that followed the 1929 Wall Street Crash.

[4] The whole family refused the request to sing at the birthday party of Adolf Hitler, and Agathe's older brother, Rupert von Trapp, a doctor, declined the offer to work in Nazi hospitals.

[22] Agathe returned to the United States in October 1939,[4] and received the unwanted publicity of being detained on Ellis Island with her family for several days.

[25] She toured Canada, South America, Australia, Austria, New Zealand, the Fiji Islands, Hawaii, and Europe.

[2] In 1956, Agathe left home to pursue a career with a friend, Mary Louise Kane, starting a kindergarten in Stowe, Vermont.

[28] She wrote her memoir, Agathe von Trapp: Memories Before and After The Sound of Music, which chronicled the true story behind the film and includes dozens of her hand-drawn maps, portraits, and other illustrations.

She started writing the book in the 1980s by traveling to Europe to research family history, sketch maps, and collect photographs.

The film The von Trapp Family: A Life of Music (2015), starring Eliza Bennett and Rosemary Harris as younger and older Agathe, respectively, was based on this book.

Agathe died on 28 December 2010, aged 97, at the Gilchrist Hospice Care in Towson, Maryland after suffering congestive heart failure.