Keiichi Sonobe is a veteran Japanese voice actor and narrator born on September 16, 1960, in Tokyo, Japan. He is affiliated with the talent agency 81 Produce, having been with them for much of his career after a prior association with Wit Promotion. His blood type is O.

Sonobe began his voice acting career in the early 1990s. His debut anime role is widely considered to be Oliver Inoe in the 1993 series Mobile Suit Victory Gundam. Around the same time, he also voiced the title character, Bow, in Heisei Inu Monogatari Bow. These early roles helped establish him in the industry, leading to a prolific and enduring career.

He is perhaps best known internationally for his long-running role in the monumental anime One Piece. Sonobe voices the character Silvers Rayleigh, the legendary former first mate of the Pirate King, a role he has played since 2009, including in the special One Piece 3D2Y: Overcoming Ace's Death! Luffy's Pledge to His Friends. His association with the series is extensive, as he has also voiced numerous other characters, including Igaram, members of the Five Elders, McKinley, and Randolph in One Piece: Protect! The Last Great Stage.

Another of his most recognizable and cherished roles in Japan is that of野口笑助 (Noguchi Emosuke), the grandfather of the character Nobuko, in the long-running anime Chibi Maruko-chan (Cherry Little Maruko), a part he has played since 1995. His filmography demonstrates remarkable versatility across genres. In the magical girl genre, he voiced Papaya in Yes! Precure 5 and Otokichi Shirabe in Suite Precure. In comedic roles, he brought to life characters like Tokoroten no Suke in Bobobo-bo Bo-bobo and the怪盗フンドシ仮面 (Mysterious Thief Fundoshi Mask) in Gintama. He has also appeared in series such as Dragon Ball Super as Zuno, Jujutsu Kaisen as Ogi Zenin, and Frieren: Beyond Journey's End as an old man with a straw hat.

Beyond anime, Sonobe's work extends significantly into other areas. He has a prominent career as a narrator for NHK, providing his voice for educational programs, historical documentaries, and children's shows. He is also a familiar presence in tokusatsu, having voiced numerous monster and villain characters in the Super Sentai series, such as in Denji Sentai Megaranger, Mirai Sentai Timeranger, and Kaizoku Sentai Gokaiger, as well as in Kamen Rider Den-O. His dubbing work includes providing the Japanese voice for Nigel Thornberry in The Wild Thornberrys. He has also lent his voice to various video games, including the Granblue Fantasy and Super Robot Wars franchises.

Throughout his career, which began in the 1990s and continues to the present day, Keiichi Sonobe has built a reputation as a reliable and skilled character actor, capable of portraying a wide spectrum of roles from elderly mentors and authority figures to comedic characters and villains. His enduring presence in long-running franchises and his work in educational broadcasting have made him a familiar and respected voice in the Japanese entertainment industry.