The Gunners have paid £3m to land the 18-year-old from Diamond Academy.
Here Starsport brings you 10 things you need to know about Arsenal’s new signing.
1) Nwakali is a box-to-box midfielder having started his career in a more attacking role.
2) He has been compared to former Arsenal captain Patrick Vieira by Diamond Academy’s manager Victor Apugo.
3) Nwakali has said his inspiration is Yaya Toure. He said: “I love watching him play because he loves to win. That’s all he wants. You can see it in the way he plays, the way he runs and even in the way he walks on the pitch.”
4) He captained Nigeria to glory at last summer’s Under-17 World Cup
5) He was named player of the tournament, following in the footsteps of the likes of Cesc Fabregas, Toni Kroos and Kelechi Iheanacho.
6) Nwakali is now part of Nigeria’s Under-20 squad.
7) Manchester City, Chelsea, West Ham, Barcelona and Bayern Munich were all linked with moves for the midfielder.
8) Former Arsenal striker Nwankwo Kanu is Nwakali’s hero and he is reported to have asked for the No.25 shirt which his compatriot wore while playing in North London.
9) Nwakali’s brother Chidiebere is part of Manchester City’s youth set-up.
10) He is represented by football agency Stellar Group who also boast Gareth Bale, Luke Shaw and Joe Hart among their clients.