Keiko Manaka is a Japanese voice actress affiliated with the talent agency Raccoon-dog. She is from Chiba Prefecture and was born on October 17. Her height is 149 centimeters, and she has blood type A. Among her personal interests are doing makeup and collecting mushroom-themed goods, while her special skills include washing dishes. She holds a standard driver's license and is a graduate of the Pro-Fit voice actor training school.

Manaka has built a career with a number of supporting roles in television anime, video games, and audio dramas. One of her earlier recurring anime roles was as Mikko Mikami, a classmate of the main characters, in the comedy series Baka and Test: summon the Beasts, a part she also reprised in its second season, Baka and Test: summon the Beasts 2. Her other anime credits from that period include small roles in Hidamari Sketch x☆☆☆, The Idolmaster, White Album, Sasami-san@Ganbaranai, and the science fiction series A.I.C.O. Incarnation. She also appeared in the theatrical anime film Tamako Love Story as a classmate.

Her voice acting work extends significantly into video games. Her game credits include roles in Octopath Traveler II, Brown Dust 2, Dragon Quest III: And Thus into Legend, the arcade game Pokemon Mezasta, as well as P.E.T.S. Academy, THE Host shiyou ze ~DX Night King~, Hakoniwa no Folklore, Heroes Placement, Shirokuma Tennis, Sangokushi Puzzle Wars, and Rinko no Lemuria: Hoshizora no Kizuna. In audio dramas, she has performed in works such as Itsuka Tenma no Kuro Usagi and Onegai, Sonna ni Kamanaide.

Manaka was announced as part of the cast for the hip-hop dance anime Wandance, which premiered in October 2025. In this series, she provides the voice for the character Rame Tokiwa. This role marks one of her more prominent recent television anime appearances.