Moukoko moved up to the under-19 team for the 2019–20 season at the age of 14, scoring six goals in his first match in the Under 19 Bundesliga in a 9–2 win against Wuppertaler SV.

[5] On 23 October 2019, Moukoko scored the opening goal in a game against Inter Milan, making him the youngest scorer in the Youth League.

[9][10] On 21 November, a day after turning sixteen, he made his debut for Dortmund as an 85th-minute substitute for Erling Haaland against Hertha BSC.

With the appearance, he became the youngest player in league history, breaking the previous record of 16 years and 334 days held by Nuri Şahin.

[12] On 8 December, Moukoko made his debut for Dortmund in the UEFA Champions League as a substitute against Zenit Saint Petersburg, becoming the youngest player in the competition's history at the age of 16 years and 18 days.

[13] He made his first start for Dortmund in the Bundesliga on 15 December against Werder Bremen,[14] and scored his first goal three days later against Union Berlin.

[16] Moukoko played 14 Bundesliga games in the 2020–21 season under Favre and his successor Edin Terzić in the forward position behind Erling Haaland (once in the starting eleven), in which he scored 3 goals.

[citation needed] In the 2021–22 season, Moukoko was also under new head coach Marco Rose in the striker hierarchy behind Haaland, Donyell Malen and sometimes Steffen Tigges.

[22] Born in Yaoundé, Cameroon, Moukoko played for the Germany national U16 team for the first time on 11 September 2017, in a 3–1 victory over Austria.

In order to protect Moukoko from too much media attention, BVB and the DFB decided not to continue using him in selected teams for the time being.