[1] With former partner, Haruna Murakami, he is the 2022 JGP Poland I bronze medalist and the 2022–23 Japan national champion on both the senior and junior levels.

[4][5] Moriguchi began figure skating in 2010 after being inspired by watching Daisuke Takahashi win the bronze medal at the 2010 Winter Olympics.

In the spring of 2021, Moriguchi decided to try pairs skating after Hamada suggested that he give the discipline a try due to his long limbs and naturally strong back.

Coached by Hamada, Narumi Takahashi, Bruno Marcotte, and Brian Shales, the pair debuted on the 2022–23 Junior Grand Prix.

They went on to compete at the 2022–23 Japan Championships, which they won, after Riku Miura / Ryuichi Kihara were forced to withdraw due to flight delays.

It was also announced that Nagaoka/Moriguchi would primarily train at the Kinoshita Academy, where they would work with coaches, Mie Hamada, Cathy Reed, Satsuki Muramoto, and Hiroaki Sato, while also making frequent trips to Oakville, Ontario, Canada to work with pair skating coaches, Bruno Marcotte and Brian Shales, at the Oakville Skating Club.

[19] They were named to the 2024 World team on the condition that they could obtain their technical minimums at the 2024 Bavarian Open or the 2024 International Challenge Cup.

[22][1] Nagaoka/Moriguchi began their season by competing at the 2024 CS John Nicks International Pairs Competition, where they finished eighth.

[1] Going on to compete on the 2024–25 Grand Prix series, Nagaoka/Moriguchi scored personal bests in all competition segments at the 2024 NHK Trophy and finish in seventh place overall.