Iyogun captained the Northampton Saints under-18s as a back row forward prior to being converted into a front row forward. He played in the
RFU Championship on loan at
Bedford Blues. On 13 September 2020 whilst still a teenager Iyogun made his
Premiership debut as a substitute and a week later made his first start in their
European Rugby Champions Cup quarter-final elimination against
Exeter Chiefs. He was named the club's Breakthrough Player of the Season in his debut campaign in 2019–20. Iyogun had made 25 appearances by the end of the 2021–22 season, including a start in the Premiership semi-final defeat to
Leicester Tigers. He signed a new long-term contract with the club in August 2022. In January 2023, he suffered an Achilles injury which ended his season. In May 2024 Iyogun was part of the side that were eliminated by
Leinster at the semi-final stage of the Champions Cup. The following month saw him come off the bench as a substitute during the 2024 Premiership final as Northampton defeated
Bath to become league champions. He signed a new contract with the club in January 2025. ==International career==