Namysłowski was born in Warsaw, Poland on 9 September 1939. He performed on the Krzysztof Komeda album Astigmatic recorded in 1965. He collaborated with such artists as Janusz Muniak, Czesław Niemen, Leszek Możdżer, Vladislav Sendecki, Michał Urbaniak and Andrzej Trzaskowski. He was the first jazz musician from Poland to release an album abroad („Lola”, 1964).
He graduated from the piano class at the Primary Music School in Krakow. After moving to Warsaw in 1954, he continued his studies at the Secondary Music School in the cello class. He made his debut as a jazz pianist in 1955, playing in the band Five Brothers, founded in the student club Hybrydy. In 1957 he joined Krzysztof Sadowski’s group – Modern Combo as a cellist, with which he performed at the Jazz Festival in Sopot. In 1958 he returned to playing the trombone and started working with the Hot Club Melomani band, with which he participated in a historic event, which was the first jazz concert at the National Philharmonic in Warsaw. He also took part in the first post-war trip of Polish jazzmen to Western Europe.
In 1960 he abandoned traditional jazz. He also began playing the alto saxophone, which soon became his lead instrument. Until 1963 he was associated with the group The Wreckers by Andrzej Trzaskowski, with which he went to the first concerts of a Polish jazz band in the United States and took part in 1962 at the prestigious festival in Newport. At the same time, he was implementing his own artistic plans. In 1961, he formed his first major group, Jazz Rockers.
His discography includes over 30 original albums, many of which were released abroad. Such albums as „Winobranie” or „Kuyaviak Goes Funky” became jazz hits and were recognized by the magazine „Jazz Forum” as albums of all time in Polish jazz. He willingly combined jazz with ethnic and classical music.