Stefanyshyn-Piper was born in St. Paul, Minnesota, United States, of Ukrainian-American heritage. Her father, Michael (Mykhailo) Stefanyshyn, now deceased, was born in Polish-governed Halychyna (today in Ukraine), and sent to work in Germany during World War II. After the end of the war, he married a German woman and they both immigrated to the U.S. Stefanyshyn-Piper's mother, Adelheid Stefanyshyn, lived in St. Paul until her death in 2018. Stefanyshyn-Piper was raised in the Ukrainian cultural community of Minneapolis–Saint Paul, is a member of "Plast" – a Ukrainian scouting organization, and speaks Ukrainian.