He is a trainee of Wisła Kraków. He scored his first goal for Wisła in the Ekstraklasa Cup match against Górnik Zabrze on 28 November 2007. Mączyński debuted in Ekstraklasa in the game versus Górnik Zabrze on 2 December 2007.
In August 2011, he joined Górnik Zabrze on a two-year contract.[2]
On 14 October 2014, he scored for the first time in international competition in a Euro 2016 Qualifying game against Scotland in group D, giving Poland a 1–0 lead in the 11th minute.
In May 2018 he was named in Poland's preliminary 35-man squad for the 2018 World Cup in Russia.[6][failed verification] However, he did not make the final 23.[7]
Career statistics
Club
Appearances and goals by club, season and competition[8][9]