Oluseye started his playing career as a striker at
Shooting Stars S.C. before transferring to
Al-Seeb Club of Oman, where he reportedly became the top scorer in the
1999–2000 Omani League and helped his team finish in third place. He attended trials held by newly established
DPMM FC of Brunei in early 2001 and signed full terms the following year, just in time for the inaugural
2002 Proton B-League. He scored seven goals before succumbing to an injury suffered at a friendly tournament between rounds, forcing a premature end to his season. Oluseye was back to Brunei for the
2003 B-League and started some hot form which would last for two seasons. He first scored four goals against IBM Bukok in an 11-0 routing of the
Temburong District side on 30 May, followed by a first-half hattrick against
Jerudong FC on 4 July. Having been made captain by the club and tasting regional club football at the
2003 ASEAN Club Championship, Oluseye led the goalscoring charts and finished with 28 goals, yet failed to defend the league title due to a 1–3 defeat by the
Armed Forces which handed the championship to unbeaten
Wijaya FC. Oluseye began the
2004 season by smashing a 23-minute hattrick against defending champions Wijaya on 9 May, eager to prove a point. His next outing was against
Kasuka FC on 11 June, when he repeated his three-goal haul in a 7–0 victory. Five days later,
Sengkurong FC were the third victims of Oluseye's triple prowess. It was not until 25 August that he scored his fourth hattrick of the season against
Kota Ranger, with DPMM running away as 11-0 winners. A fifth hattrick of the season came against
QAF FC near the end of the season and DPMM ended their campaign as unbeaten champions with Oluseye reaching the 30-goal mark. He also managed to get a
Brunei FA Cup winner's medal by beating
MS ABDB 3–1 on penalties in the final match, scoring the winning penalty. When DPMM's domestic double-winning coach
Amir Alagic took the reins of the
Brunei representative team playing in Malaysia's second tier, Oluseye was brought to the team as their import player. A hat-trick in his debut brought hope to a languishing Brunei side fighting to keep attendances, but eventually the team suffered poor form and lost their final four games and finished in mid-table. Ajayi quietly left Brunei after the season's end and studied for his coaching badges in his native
Lagos, eventually becoming head coach of Premier Football Academy in 2015. In early 2023, he was announced as the new head coach of
Osun United ==Honours==