On September 12, 2022, he revealed that he has been married to model Mariru Harada since 2020 and they had a child together. Harada announced back in 2020 that she had married and was pregnant but never revealed to the public that Shirai was the father until two years later.
Notable roles:
- Agent Six in Combatants Will Be Dispatched!
- Blanc Lapin in Ikemen Revolution
- Dayang and Drole in 100 Sleeping Princes and the Kingdom of Dreams
- Epimetheus in Dragalia Lost
- Garu in NU: carnival (as Isamu Kuroi)
- Griff A Young Captain of Deep Regrets in NieR Re[in]carnation
- Haruna Wakazato in THE iDOLM@STER: SideM
- Ian Stuart in My Next Life as a Villainess: All Routes Lead to Doom!
- Io Naruko in Cute High Earth Defense Club LOVE!
- Jaye in Arknights
- Kaname in My Dress-Up Darling
- Kei Hanada in Handa-Kun
- Keiichiro Akasaka and Francois in Tokyo Mew Mew New
- Masumi Usui in A3
- Mordred in Granblue Fantasy
- Obama in Witch Craft Works
- Percival in Divine Gate
- Ramuda Amemura in Hypnosis Mic
- Romeo Alfa in Uchuu Senkan Tiramisu
- Sasaki Shūmei in Sasaki and Miyano
- Scarecrow in BUSTAFELLOWS
- Seijirō Shimada in Bungo to Alchemist
- Sojin in Show By Rock Mashumairesh
- Soshun Murasame in Danganronpa 3: The End of Hope's Peak High School
- Takamichi Sanizen in I-Chu
- Takara Kagurazaka in Vampire Dormitory
- Takio Minato in Doreiku
- Tetsushi Tsuchikiyose in Jingai-san no Yome
- Yamato Nikaido in Idolish 7
- Yatagarasu in Akanesasu Sekai de Kimi to Utau
- Yūta Matsukaze in Wave
