Yoshimasa Hosoya is a Japanese voice actor and singer born on February 10, 1982, in Onomichi, Hiroshima Prefecture. He stands 175 cm tall and has B-type blood. His path to voice acting was inspired during high school by Yamadera Koichi's performance in the anime Martian Successor Nadesico. During his own high school years, he was a member of the kendo club and served as the head of the drama club. After graduating from Tokyo Broadcast Academy in 2002, he joined the Mausu Promotion affiliated training school and became a full member of the agency in 2004. He left Mausu Promotion on July 1, 2014, to work as a freelancer.

Hosoya's early career was heavily focused on dubbing foreign films and television dramas. His breakthrough role came in 2007 when he voiced Kuranosuke Shiraishi in the OVA The Prince of Tennis Original Video Animation National Tournament Edition Semifinal, which significantly raised his public profile. This role also launched his music career, with character song albums Medicine or...? and POISON achieving high rankings on the Oricon charts.

He has accumulated an extensive and diverse list of anime credits. He is widely recognized for major roles such as Reiner Braun in the Attack on Titan franchise, Fumikage Tokoyami in My Hero Academia, and Asahi Azumane in Haikyu!!. Other prominent performances include Kojou Akatsuki in Strike the Blood, Shichika Yasuri in Katanagatari, Orga Itsuka in Mobile Suit Gundam: Iron-Blooded Orphans, and Daryun in The Heroic Legend of Arslan. He is also a familiar presence in sports anime, with roles like Junpei Hyūga in Kuroko's Basketball, Sōsuke Yamazaki in Free!, Tetsuya Yūki in Ace of Diamond, and Otabek Altin in Yuri!!! on Ice. His filmography also includes Shin in Dorohedoro, Shirou Ogami in BNA: Brand New Animal, Doppo Kunikida in Bungo Stray Dogs, and Junk Dog in Megalobox. He also took on the role of Shotaro Hidari for the anime Fuuto PI and its film adaptation, continuing the legacy from the live-action Kamen Rider W series.

A notable pattern in his career is his involvement in long-running franchises. In the Yu-Gi-Oh! series, he progressed from voicing a minor villain in Yu-Gi-Oh! 5D's to a major antagonist in Yu-Gi-Oh! ZEXAL, and finally to the rival character Reiji Akaba in Yu-Gi-Oh! ARC-V. He also voiced the male protagonist Robin in the video game Fire Emblem Awakening and has reprised the role in several subsequent games. He took over the role of Yamato Ishida in the Digimon Adventure tri. film series from the original actor and continued in Digimon Adventure: Last Evolution Kizuna.

Hosoya was a member of the pop duo MaxBoys with fellow voice actor Toshiki Masuda, and they released a single together in 2012 before disbanding in 2013. His vocal abilities are characterized by a versatile range, from a deep baritone often used for serious characters like Reiner Braun to lighter tones for younger roles.

His achievements have been recognized with two Seiyu Awards for Best Supporting Actor, which he won in 2014 and again in 2016. In April 2017, he announced a hiatus from work to receive treatment for a throat condition and successfully returned to voice acting in August of the same year. In March 2025, Hosoya announced his marriage to a woman outside of the entertainment industry.