Moukoko turned 16 on Friday and was immediately included in Dortmund's squad for their league clash away to Hertha Berlin.
A rule change in the German top-flight earlier this year has changed the minimum age requirement from 16 and a half to 16, enabling his inclusion on the bench the day after his birthday.
And the young forward appeared in the 85th minute coming on for Erling Halaand, as he replaced the Norwegian, who fired four goals on Saturday, to mark a new Bundesliga record.
At just 16 years and one day, that mark is likely to stand for some time, showing once more Dortmund's commitment to youth.
Moukoko was one of three teenagers to make the bench for Saturday's clash, alongside Jude Bellingham, 17, and 18-year-old Giovanni Reyna, while 20-year-old striking sensation Erling Haaland started for the visitors against Hertha.
Born in Yaounde, Cameroon, where he spent the first 10 years of his life before moving to Hamburg with his father, the prodigy began to play with Dortmund's Under-17 side when he was just 12 after moving from St. Pauli and his appearance in the first team has long been expected despite his tender age.
Former coach Michael Feichtenbeiner is just one of those to have seen Moukoko who predicts big things for the forward.
The ex-Germany U16s coach told Goal and SPOX: "Such a talent does not come along in Germany every five years.
"His football skills are simply outstanding and he is a player who can make all the difference. He scored his goals everywhere - and there will be no end.
"Youssoufa will break many records in the Bundesliga.
"In an environment like Dortmund with so many young players, it's a little easier for him. You can see that in Jude Bellingham, who as a 17-year-old from England seems to have few problems keeping up with the level."
Moukoko has also made an impact at the international level, representing Germany at both U16 and U20 levels