Keiichi Nanba is a veteran Japanese voice actor and narrator born on August 26, 1957, in Yamaguchi Prefecture, Japan. He began his career in theatre after joining the Bara-za theatre troupe in 1976, following his graduation from high school. He made his voice acting debut in 1983 and officially entered the industry in 1984 with a leading role in the animated film Locke the Superman. Throughout his decades-long career, he has been known for his versatile vocal range, portraying characters from handsome heroes and villains to comedic roles. He was formerly affiliated with Aoni Production and, since September 2012, has been represented by Fujiga Office.

Nanba's career is marked by several prominent and recurring roles across anime, original video animations (OVAs), and video games. In the 1980s, he gained widespread recognition for his performance as Kazuya Uesugi in the beloved baseball anime Touch. He also became a staple voice in the Transformers franchise, appearing in five consecutive series from the first generation through Victory, voicing characters such as Broadcast, Twincast, Wilder, Leozack, and Lio Kaiser. Another significant early role was Bat in Fist of the North Star 2. He is also well-known for his work in Saint Seiya, where he voiced the dual roles of the Gold Saint Pisces Aphrodite and Julian Solo, who is the host for Poseidon; he later reprised the role of Aphrodite in the 2018 series Saint Seiya: Saintia Shō.

In the 1990s and beyond, Nanba continued to take on diverse and memorable characters. He voiced Andy Bogard in the Fatal Fury and The King of Fighters video game series, and Axl Low in the Guilty Gear series, a role that was reportedly created specifically for him. His extensive filmography includes Gurio Umino and Zoisite in Sailor Moon, Shunichi Sugishita in Blue Seed and its sequel, Junta Momonari in DNA², Ryu Hayabusa in the Ninja Ryūkenden (Ninja Gaiden) OVA, and Itomimizu in One Piece. He also played Ryu in the OVA Gdleen, Alex in Wizardry, and Kazuya Uesugi in the film Touch: Sebangou no Nai Ace.

Beyond animation, Nanba has an extensive career in dubbing foreign films and television series and is particularly noted for his long-running role as the voice of Ultraman Hikari in the Ultraman metaseries, starting with Ultraman Mebius in 2006. In addition to his performance work, he has worked as a narrator for television programs and is dedicated to training new talent as a representative and chief lecturer at the Shoto Actor's Gymnasium. Among his notable students is Megumi Oohara, the voice of Nobita Nobi in the 2005 Doraemon anime series.