Walch was born on February 1, 1971 in Davenport, Iowa with German descent. She started her professional acting career on stage at age 11. At 16 she attended the North Carolina School of the Arts, majoring in voice (soprano). In 1989, she received the Presidential Scholarship and went to the UNC School of the Arts in Winston-Salem, North Carolina. After UNC, she went to Chicago, Illinois, where she did plays, including The Rise and Fall of Little Voice on Broadway, where she won the Outer Critics Circle Award for her performance as the title character. As a high school senior, she was awarded as a Presidential Scholar in the Arts in drama. In 2005 she graduated summa cum laude from UCLA with a B.A. in American Literature and founded the Hillside Produce Cooperative, a free exchange of local, organically grown food, for which she was named runner up Citizen Entrepreneur of the Year by Global Green USA. Hynden has been married to Sean McDermott since 1999.