Game Designer Research

One of the most successful gaming franchises, Pokemon took the world by storm and continues to be at the forefront of handheld gaming.

The original concept came from Satoshi Tajiri; "[He] claims that the joining of two Game Boys via a link cable inspired him to create a game which embodied the collection and companionship of his childhood hobby, insect collecting."

source = http://en.wikipedia.org/wiki/Satoshi_Tajiri

However, the most notable game designer / programmer  throughout the games iterations would be Shigeki Morimoto. "[He] is a game designer and programmer (among other various roles such as Pokémon adviser and Pokémon designer), currently working at Game Freak. He has been involved in nearly every main series Pokémon game since Pokémon Red and Green Versions. He is most notable for the creation of the Pokémon Mew, which also happens to be his favorite Pokémon. He also appeared as an NPC in Black, White, Black 2, and White 2."

source = http://bulbapedia.bulbagarden.net/wiki/Shigeki_Morimoto

Shigeki Morimoto with HeartGold and SoulSilver.

The Pokémon game series has held true with it's core game mechanics;

Pokémon collecting (completing the Pokédex)

Turn-based battling (although evolving into single, double, triple and rotation battles)
Ability to customise (Through team of 6, stat training, move selection, level etc.)