Born in Sieradz, Poland, Stępiński started his career playing for youth sides Piast Błaszki and Pogoń-Ekolog Zduńska Wola. In 2011, he signed for Ekstraklasa club Widzew Łódź, going on to make 33 appearances and scoring five goals over two seasons.
On 31 August 2017, he was loaned to Italian side Chievo.[3]
Hellas Verona
On 2 September 2019, he signed for Verona. The deal is a loan from Chievo with obligation to buy at the end of the loan.[4]
Lecce
In October 2020, he signed for Lecce with an option to buy.[5]
Aris Limassol
On 6 August 2021, he was loaned to Cypriot side Aris Limassol with an option to buy at the end of the season.[6] He made his debut on 22 August 2021, where he played for 65 minutes. On 31 August 2022, Stępiński returned to Aris on a permanent basis.[7] He helped the team win their first ever domestic championship.
Omonia
In the 2024 January transfer window, Stępinski moved to Omonia for an undisclosed fee.[8]
International career
Stępiński represented Poland at various youth levels. He made his first senior appearance on 2 February 2013 in an international friendly against Romania. Poland won 4–1, with Stępiński being subbed on in the 84th minute.[9]