In the following campaign, he finished as the league's top scorer with 26 goals, a record-high for an African player, as he helped Napoli win a first Serie A title in 33 years.

His impacts off and on the pitch with other members of the team made them reach the final of the African Cup of Nations in 2023 of which they lost to the host country Ivory Coast.

[9] Osimhen finished in eight place at the 2023 Ballon d'Or ceremony, becoming the first Nigerian to make the top ten of the French award.

[18][19] Out with an injury upon his arrival,[20] he made his Bundesliga debut for Wolfsburg on 13 May, coming on as a substitute in the 59th minute in a 1–1 draw against Borussia Mönchengladbach.

Osimhen was in the squad for both matches, receiving a cameo at the end of the second leg with Wolfsburg's participation in the next Bundesliga confirmed, as they won 2–0 on aggregate.

[22] Osimhen made two more starts for the rest of the campaign, playing the full match against Werder Bremen on 11 February and being replaced at the half by Daniel Didavi against Hertha Berlin on 31 March.

He also appeared in one game of Wolfsburg's DFB Pokal campaign, replacing midfielder Josuha Guilavogui for the last ten minutes of their 1–0 defeat to Schalke in the quarter-final.

[24] On 22 August 2018, Osimhen joined Belgian club Charleroi on a season-long loan deal, having failed to score in any of his 16 appearances with Wolfsburg.

After a successful spell with the Belgian side, playing 36 games and scoring 20 goals, Charleroi activated their option to acquire Osimhen following his satisfactory performances while on loan.

[36] Ten days after the move, he made his Ligue 1 debut for the club on 11 August, scoring a brace in a 2–1 win against Nantes.

[37] Two weeks later, he scored another brace in a 3–0 home win against Saint-Étienne for his third game in France, his performance earning him a rating of 8/10 in French sports newspaper L'Équipe.

[40] In March, a report published by the league showed that Osimhen was the player who has most broken the 35 km/h (21.75 mph) barrier with seven sprints above this speed, ahead of Kylian Mbappé.

[48] On 13 November, during an Africa Cup of Nations qualifying game played whilst on international break with Nigeria, Osimhen was stretchered off injured.

While recovering from the injury, Osimhen was authorised by his club to spend time in his home country, where he got a chance to celebrate his birthday.

[50] This positive test, together with his shoulder injury, kept Osimhen away from action until his return to the side on 29 January 2021, when he was subbed on for around twenty minutes of Napoli's Coppa Italia win against Spezia.

[52] In November 2021, Osimhen suffered a horrific head injury and a fractured skull and eye socket in Napoli's 3–2 loss to Inter Milan at San Siro.

[55][56] On 12 October 2022, Osimhen scored his first Champions League goal with Napoli in a 4–2 win over Ajax, which secured their qualification to the knockout phase.

[62] In the Champions League round of 16, Osimhen scored three goals over two legs for Napoli against Eintracht Frankfurt, which ended in a 5–0 win on aggregate and a first-time qualification to the quarter-finals.

[68] A hamstring injury during Nigeria's 2–2 friendly draw to Saudi Arabia on 16 October 2023 caused him to miss four regular season games and two Champions League group stage matches.

[74] Over the course of the summer transfer window, there was much speculation that Osimhen would leave Napoli with Al-Ahli, Chelsea, and PSG all heavily linked with the player.

[78] On 31 August, Osimhen was excluded from Napoli's Serie A squad for the season and stripped of his number, with the shirt being handed to new signing Romelu Lukaku instead.

[79] On 3 September, Turkish Süper Lig club Galatasaray opened talks to take Osimhen on loan until the end of the 2024–25 season.

[29] In March 2019, Osimhen was released from the Super Eagles squad to represent the Nigerian U23 side as they were two goals down against their Libyan opponent.

[103] Osimhen is a right-footed centre-forward known for his physical presence, athleticism, strength, directness, runs into space, eye for goal and linkup play.

Standing at 185 cm tall, Osimhen's wide frame and ability to hold up the ball make him an effective target man, capable of bringing others into play and contributing to the build-up of attacking moves.

Osimhen's stamina, work rate and willingness to press opponents make him an active contributor to his team's defensive efforts.

[108][109] He used to be compared to fellow young strikers Kylian Mbappe and Erling Haaland, until he joined Turkish Super League.