Kat Harley was born and raised in Poznan, Poland, where she pursued acting and ballroom dancing. She participated in school and community theater productions, and competed in national ballroom dancing events. She was first featured in a Polish TV movie, Powrót do Polski (1988).
After coming to the United States in September 1989, Kat had a lucrative career in the investment banking industry, but something was missing. In 2009, she was offered a supporting role in the music video, "Just Watch Me", and later, in "I've Got A Secret". This led her to leave the investment business, and become a freelance translator, which gave her the freedom to further pursue a career in acting.