From Bulbapedia, the community-driven Pokémon encyclopedia.
James Carter Cathcart (born March 8, 1954 in West Long Branch, New Jersey), often credited as simply Carter Cathcart, is an American voice actor, pianist and vocalist who currently works for the English-language dub of the Pokémon anime. He has also been credited under his pseudonyms Billy Beach and Jimmy Zoppi. Besides voice acting, he is also a musician. He plays bass, electric guitar, keyboards and drums.
Cathcart is one of the original actors on the anime. Aside from his role as Gary Oak, he mainly played characters of the day until Pokémon: Battle Frontier, when TAJ Productions and The Pokémon Company International, then known as Pokémon USA, took over the dub. When his voice-acting duties were increased by becoming the voice of James and Meowth of Team Rocket as well as Professor Oak, he took on the pseudonym Billy Beach. Previously, for the 4Kids-dubbed episodes of the anime, Cathcart went under the pseudonym Jimmy Zoppi, his most well-known pseudonym.
Since season 5 he has been responsible for the script adaptation of episodes, a role which he still performs on the show. As script adapter, in 4Kids-dubbed episodes he was credited as Carter Cathcart, the name he now uses in his voice acting duties as of Season 14 and in TPCi-dubbed episodes he is credited under his full name, James Carter Cathcart.
Following the retirement of Kayzie Rogers at the start of Sun & Moon series, he is now the longest serving voice actor in the English dub. They are the only English voice actors in the series to work on the dub of every season of the anime so far.
Carter Cathcart posted anonymously under the name "Old Guard Truthseeker" on Bulbagarden Forums and Serebii.Net Forums during the Pokémon USA recasting controversy. He among other things criticized 4Kids, and praised the performance of himself as James, saying he is better than the previous two voice actors of James.
Famous non-Pokémon roles
Carter Cathcart is a member of Voices for Fosters  alongside fellow Pokémon voice actresses Sarah Natochenny and Lisa Ortiz.