Akiko Yajima is a veteran Japanese voice actress born on May 4, 1967, in Kashiwazaki, Niigata Prefecture. A graduate of Shukutoku Junior College, she entered the voice acting industry in 1989, making her debut in the lead role of Eriko Tamura in the television anime Idol Densetsu Eriko. Her path to voice acting began after being scouted by a production agency manager while performing in a stage play, having studied acting at a night school while working as a salesclerk.

Yajima is widely recognized for her extensive and versatile body of work, which spans a broad spectrum of character types, from young boys to elegant heroines. Her most iconic and long-running role was as the titular character, Shinnosuke Nohara, in the immensely popular anime series Crayon Shin-chan. She provided the voice for Shinnosuke for 26 years, from the show's debut in 1992 until June 2018. Yajima stepped down from the role at her own request, citing the increasing difficulty in maintaining the character's unique voice naturally and the strain it placed on her performances for other roles. Her final performance as the character was in the 26th feature film, Eiga Crayon Shin-chan Bakumori! Kung-Fu Boys ~Ramen Tairan~. This role brought her widespread fame, and her work as Shinnosuke on a character single reportedly sold over 360,000 copies, making it one of the best-selling anime character songs in Japan at the time.

Demonstrating her range beyond comedic child roles, Yajima is also well-known for her portrayal of the complex and graceful Relena Peacecraft in Mobile Suit Gundam Wing. She voiced the character in the television series and its sequel, Mobile Suit Gundam Wing: Endless Waltz. Another significant role was as Kohaku in the long-running series Inuyasha, a boy whose innocence is manipulated for villainous purposes. Her versatility is further highlighted by her performance in Blood+, where she voiced two starkly contrasting characters: the gentle boy Riku and his twin sister, the volatile and dangerous Diva. In the magical girl genre, she voiced Mipple in the original Futari wa Pretty Cure and its film appearances, including the Precure All Stars series.

Yajima's extensive filmography includes a multitude of other notable roles across television, film, and OVA. These include Sally Yoshinaga in The Brave Express Might Gaine, Paffy Pafuricia in Lord of Lords Ryu Knight, R. Dorothy Wayneright in The Big O, Kuu in Haibane Renmei, Mitsuru Tsuwabuki in Revolutionary Girl Utena, and Anita in the Night Warriors: Darkstalkers' Revenge OVA. She has also had roles in major film franchises, such as Akisu in One Piece: Nejimaki Shima no Bōken and Rani Chawla in the CG film Resident Evil: Degeneration. Other listed roles include Dolly in DT Eightron, Long Long in Pururun! Shizuku-chan, Shiho Katagiri in Idol Fighter Su-Chi-Pai, and Ki in The Tower of Druaga: the Sword of Uruk.

Throughout her career, Yajima has been affiliated with several agencies. She was initially with Production Baobab from her debut until around 2010, after which she worked as a freelancer in a business partnership with AIR AGENCY. In August 2024, it was announced that she had joined Across Entertainment under the name Aki Uechi. Yajima is regarded in the industry for her exceptional skill and wide vocal range, often being described as a voice actor with a "seven-color voice". She is known for maintaining a traditional approach to her craft, focusing on her work as a behind-the-scenes performer.