Uta was of Welsh-German ancestry on her father's side and Danish on her mother's side.
Uta Hagen was born on June 12, 1919, in Göttingen, Germany to an artistic family. Her mother, Thyra A. (Leisner) Hagen was a Danish opera singer and teacher, and her father, Oskar Hagen, started the Handel Opera Festival in Göttingen. Six years after Hagen's birth, the family emigrated to the United States, moving to Madison, Wisconsin. When she was six, her father accepted a position at the University of Wisconsin and moved the family to Madison. It was here, in the Midwest, where Hagen was raised until the age of sixteen. While growing up, Hagen attended the theater regularly with her parents, both in the United States and on frequent trips to Europe.