Tadaaki Doi is a Japanese voice actor born on January 7 in Hyogo Prefecture, Japan. He is affiliated with the talent agency ARISE PROJECT and graduated from the Nihon Narration Engi Kenkyuujo, also known as the Nihon Narration Acting Institute. He speaks the Kansai dialect naturally.

Doi began his professional voice acting career in 2018. He has built a versatile portfolio by taking on a wide range of supporting and background roles across many popular anime series. His anime work includes roles in Fairy Tail, BOFURI: I Don't Want to Get Hurt, so I'll Max Out My Defense, Spy Classroom, Kingdom, The Seven Deadly Sins: Four Knights of the Apocalypse, Giant Beasts of ARS, Undead Murder Farce, and Metallic Rouge. He has also contributed to animated films, including a role in the movie Suzume.

Beyond television and film, Doi has voiced characters in web anime such as Battle Spirits Mirage and Ghost in the Shell: SAC_2045, in which he played the role of Kenji Isshiki. His work extends to video games, with roles in major titles like Valkyrie Elysion, Mobile Suit Gundam Battle Operation Code Fairy, SD Gundam Battle Alliance, Final Fantasy XIV, and Remnant: From the Ashes. He is also active in dubbing foreign media, lending his voice to Japanese-language versions of productions such as Shantaram, True Story, and Puss in Boots: The Last Wish. In addition, he performs in audio dramas and voice drama CDs, including the series The Aristocrat Pig, But My Past Life's Memories Emerged, So I'll Raise My Chick Brother, in which he plays Sebastian.

Doi holds qualifications including a standard driver's license, Grade Pre-2 of the Eiken English test, and Grade Pre-2 of the Kanji Kentei. His special skills include playing with traditional Japanese toys such as juggling beanbags (otedama), spinning tops (koma), playing with a kendama, and walking on stilts. His hobbies include watching baseball, cooking, and riding a unicycle.