Jun Oosuka is a Japanese voice actor born on May 24, 1979, in Fukuoka Prefecture, Japan. He is affiliated with the talent agency Amuleto, having joined in October 2014 after a period as a freelance performer and prior membership with the agency Mouse Promotion. His interest in voice acting began in childhood, inspired by a friend's father who worked in the industry, and he pursued this goal through formal training, graduating from both the Showa College of Music Voice Acting Department and Eizo Techno Academia.

Oosuka's career, which began in the late 1990s, encompasses a wide range of roles in television anime, video games, and drama CDs. He is known for his versatility, bringing to life characters that can be whimsical, serious, or comical. In addition to anime, his work includes dubbing foreign films and television series, as well as appearances in stage plays and radio programs. He frequently participates in live events and music performances related to his various projects.

Among his prominent anime roles is Mika Kagehira in the multimedia franchise Ensemble Stars!. He also voiced Tsubaki, the mature and level-headed cook of the group, in the original anime series Fena: Pirate Princess. His other television anime credits include the role of Ogawa in both Haruka Nogizaka's Secret and its second season, Haruka Nogizaka's Secret: Purezza, and Shingo Ōhashi in PetoPeto-san.

Oosuka has built a career with recurring roles across several major franchises. He is well-recognized for his work in The Prince of Tennis franchise as Senri Chitose, also known as Chitose Senri. He has an ongoing association with the Touken Ranbu franchise, voicing the character Hakata Toushirou in the anime series Touken Ranbu: Hanamaru and related games. His role as Shunsuke Yoshino in Sanrio Boys is another example of his work in series based on popular character brands. Beyond these, his extensive filmography includes guest roles in long-running series such as Bleach, Naruto, and Shakugan no Shana, as well as a recurring part as Keisuke in Major.

In the realm of video games, his voice work is similarly extensive. Beyond reprising his anime roles in games like Ensemble Stars! and Touken Ranbu, he has contributed to major titles such as Fire Emblem Fates, where he voiced the character Flannel. Oosuka is also active in the world of drama CDs and character songs, often performing music associated with his characters, which have become popular with fans. His dedication to character portrayal extends to live performances, where he is known for embodying his roles with commitment, such as maintaining a doll-like stillness during a stage song to match his character's persona.