Kasia Kaczmarek was born in Poland and grew up in Perth, Western Australia. Her parents are Kristof Kaczmarek and Marta Kaczmarek. Kasia attended the Victorian College of the Arts (VCA) and later moved to New York, USA to study at the William Esper Studio. Her television debut was in a guest starring role on The Circuit (2007). As of 2019, she splits her time between Australia and Poland.