Gyeong-Su Hyeon is a South Korean voice actor born on April 1, 1974. He began his professional career in 2003 when he joined the voice acting division of On Media, now known as Tooniverse. He has been active as a freelancer since 2006.

Hyeon is best known for his extensive work dubbing Japanese anime into Korean. One of his notable early roles is Fuumin, also known as Okometsubu Fujiyama, in the comedy series Sexy Commando Gaiden: Sugoi yo!! Masaru-san. His filmography includes a wide range of prominent characters in major anime series. He voiced Ikkaku Madarame in Bleach, Youhei Sunohara in Clannad, and Greed in Fullmetal Alchemist: Brotherhood. He also took on leading roles such as Kaiji in Kaiji: Ultimate Survivor and Rob Lucci in One Piece. In the long-running series Naruto and Naruto Shippūden, he provided the voice for Kiba Inuzuka, and in Gintama, he voiced Tatsuma Sakamoto.

Beyond these, his voice acting credits span numerous other series, demonstrating his versatility. These include roles as Jumeokbab in Air Gear, Aiber in Death Note, Thomas O'Brian in Ashita no Nadja, and Dantalion in Shakugan no Shana. He also voiced characters in Tantei Gakuen Q, Kaleido Star, Reborn!, and The Gokusen. In addition to television series, his work includes film dubbing, such as his role as Katsuhiko Jinnouchi in the Korean dub of the animated film Summer Wars. His career also encompasses voice work for live-action television series, including the Korean dubbing of characters in the Kamen Rider franchise, such as Ryu Terui in Kamen Rider W.