Katie O'Hagan was born in Illinois, the third of six children. She grew up in the town of Crystal Lake. Upon completing her sophomore year at Northern Illinois University, she auditioned for the entertainment department for the college program internship at Walt Disney World in Florida. For the next two years, Katie worked as a character actress in both Florida and Japan. She returned to the United States in 2003 and began attending Marist College in Poughkeepsie, NY to finish her degree in Communications. At Marist, Katie received numerous recognitions for her acting talent, playing principle roles in several Marist College Council on Theatre Arts (MCCTA) productions, including Claire in "Proof" and Columbia in "The Rocky Horror Show." In January 2005, she was nominated and attended the prestigious ACTF competition for selective college actors. In the summer of 2005, Katie was cast as the lead in an independent feature film, "RiffRaff" that was filmed in Chicago.