[1] After winning the German U17 championship with Eintracht Frankfurt in June 2010, Kittel was capped in the professional squad for the 2010–11 season.

Bundesliga side FC Ingolstadt for three seasons, Kittel transferred to Hamburger SV on 18 June 2019, signing a four-year contract.

[2] On 20 July 2023, Kittel signed a three-year deal with defending Ekstraklasa champions Raków Częstochowa.

[4] On 24 August 2024, he signed with Swiss Super League side Grasshopper Club Zurich for an undisclosed fee.

This biographical article related to association football in Germany, about a midfielder born in the 1990s, is a stub.