Seo Munseok is a South Korean voice actor who has been active in the industry since the late 1980s. He joined the KBS Voice Actor Association in 1988 and transitioned to freelance work in 1992, later also serving as the 29th president of the KBS Voice Acting Association.

He is known for a wide vocal range, allowing him to portray deep and profound characters as well as sharper voices for comedic roles. His notable villain role is Crocodile, also known as Mr. 0, in the long-running series One Piece. In the same series, he also provides the voice for Dracule Mihawk and Portgas D. Ace. Another significant role is the hot-blooded character Kamina in Tengen Toppa Gurren Lagann. He also voices Childman Powderfield in the Orphen series.

Beyond these major roles, his career includes a substantial amount of work in dubbed animation, taking on various supporting and lead roles in numerous productions.