He was selected in Nigeria's 18-man squad for the 2016 Summer Olympics,[5] after helping them qualify for Rio with his decisive goals. With Nigeria, he won the Olympic bronze medal. Junior Ajayi helped Egyptian giants Al Ahly secure 2 CAF Champion Leagues, 2019–20 and 2020–21. However, following the arrival of Percy Tau and Luís Miquissone, he was never selected by Pitso Mosimane for matches and demanded Al Ahly to terminate his contract. He eventually found himself in Libyan side Al Nasr-Benghazi. On July 30, 2022, Junior Ajayi returned to Egypt by signing for Alexandria-based Smouha.