After graduating from high school, Wasick trained in Poland with her brother Robert Wilk at the AZS AWF Katowice swim club before the 2012 Olympics in London. After the Olympic Games she went on to study at the University of Southern California where she swam for coach Dave Salo for four years. Wasick has shown great individual scoring ability while lending a strong hand on relays.[5] She's a twelve-time All-American and has scored four times individually at the NCAA Championships and is a six-time career Pac-12 finalist. At the 2016 NCAA Championships, she posted career bests with a third in the 100y freestyle. She also led off USC's first place 400y free relay that set a school record.
After the 2016 Olympics in Rio de Janeiro she retired from swimming due to injury. In 2018 she made a comeback to competitive swimming, first starting with the Las Vegas Masters team. She holds two American masters records in the 50 and 100 freestyle (25-29 age group short course yards records). Later in 2018 she joined the University of Nevada, Las Vegas Pro Group coached by Ben Loorz and Patrick Ota.
In 2022, she won the silver medal in the 50m freestyle at the 2022 World Aquatics Championships in Budapest becoming the second Polish female swimmer, after Otylia Jędrzejczak, to win a long course world championship medal.[8]
Her father, Zbigniew Wilk, is a former boxer. Kasia has three siblings, two elder brothers who also practice swimming and a sister who competed in track and field. She says her brothers inspired and motivated her to take up swimming.[10] She received a bachelor's degree in psychology from the University of Southern California. She currently lives with her husband, Matthew Wasick, in Las Vegas.[11]
