Janni-Luca Serra was born in Springe, Lower Saxony, and began playing soccer in the youth teams of SG Bredenbeck-Holtensen, where he is still an honorary member.

After winning one championship with the under-17s and two with the under-19s, Serra made his debut for Borussia Dortmund II on 30 July 2017, in a home game against Rot-Weiss Essen in the Regionalliga West.

[5] He scored his first goal in professional football on 22 September 2018, with a last minute header in a 2–2 draw against his former club VfL Bochum.

He retained his place in the starting XI in the following season under new head coach Ole Werner, scoring a total of eight goals in 19 league games and two cup appearances until February 2020.

[5] On 4 July 2023 Danish Superliga club AGF confirmed, that they had signed Serra as a free agent on a 4 year contract.

[9] Janni Serra has made 31 appearances for four different DFB junior national teams so far, including ten for the German under-17s (with whom he finished second at the 2015 European Championship) and four for the under-19s.

[1] On 21 July 2016, he tore his ACL during a match at the 2016 UEFA European Under-19 Championship and underwent a total of four surgeries during the remainder of 2016.

His late father Ralf also used to play low-level soccer and worked for the Lower Saxony Football Association as a coach.