Born on 16 October 2003 in Katowice, Poland, Mateusz Konrad Musiałowski began playing football at the age of five with Ajaks Częstochowa. He later joined the academy at Raków Częstochowa before a loan spell at Skra Częstochowa, and then moved to SMS Łódź, where he made a striking impression at youth level, scoring 133 goals in 88 games.
After trials with Arsenal, Musiałowski joined Liverpool in August 2020, signing his first professional contract in July 2021. He earned wider attention in March 2021 when a solo goal against Newcastle United's under-18s was named the under-18 Premier League Goal of the Season. His first-team debut came on 14 March 2024, when he came on as a second-half substitute in a 6–1 Europa League victory over Sparta Prague at Anfield, making him only the second Polish player ever to represent Liverpool and the first Polish outfield player to do so.
Musiałowski departed Liverpool at the end of the 2023–24 season and signed a three-year deal with Cypriot club Omonia in August 2024. He went on to win the Cypriot First Division title with the club in the 2025–26 season.
A versatile and direct attacking midfielder, he is comfortable operating in a central role or out wide on either flank. Omonia see him as a key part of their squad going forward. Musiałowski has also represented Poland at multiple youth international levels.