Ai Nonaka is a Japanese voice actress and singer affiliated with Aoni Production who has been active in the industry since her debut in 2000. She was born on June 8, 1981, in the Sawara-ku ward of Fukuoka City, Japan. Nonaka's interest in voice acting began in her childhood after watching the anime Yu Yu Hakusho and becoming captivated by the character Kurama, voiced by Megumi Ogata. This admiration led her to pursue a career in acting. During high school in Fukuoka, she was the head of the drama club and initially aspired to perform with the all-female Takarazuka Revue, but she was ultimately unable to meet the height requirements for its male roles. She then enrolled in the Tokyo branch of Aoni Production's training school, Aoni Juku, graduating as part of its 21st class.

Nonaka is known for her versatile vocal range, often portraying characters who are cheerful, sweet, and optimistic, though she has also taken on more serious and complex roles. One of her most prominent and enduring roles is Kyoko Sakura in the acclaimed Puella Magi Madoka Magica franchise. She has voiced the character in the original 2011 television series, its sequel films, including Puella Magi Madoka Magica The Movie: Walpurgisnacht: Rising, and the spin-off game and anime Magia Record: Puella Magi Madoka Magica Side Story. Another significant early role was Fuko Ibuki in the visual novel-based anime Clannad and its sequel Clannad After Story, a character she also reprised for the 2021 crossover series Kaginado.

Throughout her career, Nonaka has established frequent collaborations, particularly with the animation studio Shaft and director Akiyuki Shinbo. This partnership is most evident in her role as the perpetually optimistic Kafuka Fuura across multiple installments of the Sayonara, Zetsubou-Sensei series, including Sayonara, Zetsubou-Sensei, Zoku Sayonara Zetsubou-Sensei, and its various OVAs. She also voiced Yayoi Fushimi in Shaft's Natsu no Arashi! and its second season. Another recurring role early in her career was Konoka Konoe in the various anime adaptations of Mahou Sensei Negima!, including the 2005 series, Negima!?, and multiple OVAs. In the long-running series Gintama, she provides the voice for the character Pirako Chin.

Beyond anime, Nonaka has an extensive portfolio in video games. She voices the character 416 in the popular mobile game Girls' Frontline, a role she has also played in its anime adaptation, Dolls' Frontline. She is well-known to game fans as Honoka in the Dead or Alive fighting game series, including Dead or Alive 5 Last Round, Dead or Alive 6, and related spin-offs. Her other notable game roles include Towa Herschel in The Legend of Heroes: Trails of Cold Steel series, Bao Sanniang in the Dynasty Warriors series, and Frankenstein's Monster in the mobile game Fate/Grand Order and the anime Fate/Apocrypha. She also voices the character Tora in Xenoblade Chronicles 2.

In addition to her voice work, Nonaka has pursued a career as a singer, releasing multiple singles and albums under the music label STARCHILD. She was also a member of the voice actor unit Drops, alongside Akemi Kanda, Tomoko Kaneda, Mariko Kōda, and Ryōko Shiraishi. Her work extends to radio hosting, where she is known for her candid and lively commentary that contrasts with the often sweet characters she plays. She has also taken on dubbing roles for foreign television, such as voicing Connie in the Japanese version of Steven Universe. Outside of her professional life, Nonaka is a licensed aromatherapist and an enthusiast of marathons and professional wrestling.