Okumoto made his debut in formula racing in 2022 in F4 Japanese Championship with Team Heroes.

[1] Okumoto then moved to TGR-DC Racing School for 2023 where he clinched 2 podiums and finished 9th in the standings.

[2][3][4] Okumoto will make his debut in Super GT in 2025 as he will join Goodsmile Racing & TeamUKYO for round 3 in Sepang International Circuit along with Yuhki Nakayama as the regular drivers Nobuteru Taniguchi and Tatsuya Kataoka prioritize Spa 24 Hours.

[5][6] Okumoto made his debut in Super Taikyu in 2023 as he race in ST-2 class with Kobe Toyopet Motor Sports in 2023 alongside Kengo Ichijo, Rin Arakawa, and Jiei Okuzumi.

Okumoto then steps up to ST-X class in 2025 where he joins TKRI alongside team owner Tatsuya Kataoka, Yuhki Nakayama, and Daisuke Matsunaga.