Sakaguchi began his senior competition career in 2015, competing for Sutekina Racing Team in the final four rounds of the F4 Japanese Championship.

[citation needed] He returned to F3 in 2017 with Honda support, finishing an improved 6th in points, netting his first podium in the series at the penultimate race at Sugo.

[8] However, Sakaguchi once again was unable to make it to the grid, crashing on the warm-up lap and failing to officially register his Super Formula debut.

[4] For 2021, Sakaguchi secured a full-time ride in Super Formula with P.mu/cerumo・INGING, replacing retiring two-time series champion Hiroaki Ishiura.

During 2020, Sakaguchi also played the role of substitute on two occasions, initially replacing Heikki Kovalainen in TGR Team SARD's GT500 class entry at Fuji in July.

[10] For 2021, Visa issues for Frenchman Sacha Fenestraz enabled Sakaguchi to add a part-time campaign in the GT500 class of the Super GT series.

Ahead of 2022, Sakaguchi moved to the GT500 class full-time, pairing with Yuji Kunimoto in the #19 TGR Team WedsSport Bandoh entry.