Yudai Chiba is a Japanese actor and model who was born on March 9, 1989, in Miyagi Prefecture. He began his entertainment career as a model, becoming an exclusive model for the magazine Choki Choki in 2007. His on-screen acting debut came in 2010 when he landed the lead role of Alata, also known as Gosei Red, in the long-running super sentai series Tensou Sentai Goseiger.

Chiba's entry into voice acting occurred in 2011 with his participation in the Japanese dub of the film Hop, where he worked alongside veteran voice actor Kōichi Yamadera. However, his debut in anime voice acting came later, in December 2015, when he voiced the character Kentaro Kato, a young,正义感のある (justice-seeking) detective, in the anime series The File of Young Kindaichi Returns. This role corresponds to the character Ryūtaro Kobayashi mentioned in the query.

Following his anime debut, Chiba took on several notable voice roles. In 2017, he voiced Touma Tsukinami in the animated film Yo-kai Watch Shadowside: Oni-ō no Fukkatsu. The following year, he joined the cast of the long-running Pokémon anime, providing the voice for the character Ilima in the Sun & Moon series. His other voice work in anime includes a role in Shitsuren Chocolatier. Beyond anime, Chiba has also lent his voice to dubbed versions of foreign films, such as providing the Japanese voice for the main character in the live-action/CGI film Peter Rabbit and its sequel.

Chiba is affiliated with the talent agency Japan Music Entertainment. His career is marked by a frequent blending of live-action and voice acting roles, often within franchises popular with young audiences. This pattern began with his breakout role in Tensou Sentai Goseiger and has continued with his work in major anime properties like Yo-kai Watch and Pokémon. A notable achievement in his broader acting career was winning the Newcomer of the Year award at the 40th Japan Academy Prize for his role in the 2016 film The Magnificent Nine.