After compiling a perfect record of 5–0, on 24 August 2018, Ajagba scored the fastest victory in boxing history in a match against Curtis Harper, winning in one second via disqualification after Harper walked out of the ring in protest over a pay dispute. After improving to 12–0, on 7 March 2020, Ajagba fought
Răzvan Cojanu. In a one-sided fight, Ajagba dismantled his opponent round by round, and managed to score knockdowns in both the eighth and ninth rounds. In the ninth, Cojanu took a knee with 2:25 left in the round, and the referee decided to stop the fight. In his next fight, Ajagba made his
Top Rank debut and fought Jonathan Rice on 19 September 2020. The fight ended up being less entertaining than expected, especially because Ajagba was not throwing a lot of punches. He did however, still do enough to hurt Rice and earn a unanimous decision victory. Ajagba secured another victory in his 15th fight, knocking out Brian Howard in the third round on 10 April 2021. Ajagba faced off against undefeated
Frank Sánchez on 9 October 2021 on the undercard of
Tyson Fury vs. Deontay Wilder III. Ajagba was knocked down en route to a unanimous decision defeat, with scores of 98–91, 98–91 and 97–92 for Sánchez. On 4 November 2023 in Stateline, Nevada, Ajagba faced his old rival
Joseph Goodall in a 10-round bout at heavyweight. He won by technical knockout in the fourth round. Ajagba fought
Guido Vianello on 13 April 2024 in Corpus Christi, Texas, USA. He won the fight by split decision. He faced
Charles Martin at
Meta Apex in
Enterprise, Nevada, USA, on 15 February 2026. Ajagba won by stoppage in the fourth round. ==Professional boxing record==