Łukasz Kadziewicz was born in Dobre Miasto, Poland. He was married to Kamilla. Their daughter Amelia was born on March 21, 2006. Łukasz and Kamilla were divorced in 2008. He has since married for a second time, to Barbara (née Gołąb).
When Łukasz was a member of the Polish national team he created the "Kadziu Project". He filmed videos that showed how the Polish team prepared for matches and their lifestyle during tournaments (for example the Olympics in Beijing, 2008). When Kadziewicz ended his career in the national team, Krzysztof Ignaczak took up his idea, continuing this work under the name "Igłą Szyte". In 2013 Kadziewicz reactivated the "Kadziu Project", but instead of showing life in the national team, he now films interviews with other volleyball players and talks about his thoughts related to volleyball.