Pokemon Red and Blue came out on Gameboy Color in 1996 in Japan. They were released in North America two years later as well as the Japanese exclusive Pokemon Green.
I think the first time I remember playing was on my sister's clear purple Gameboy Color, i think it was Pokemon Blue? (around 2002)
The first episode of the first season (Indigo League - Kanto Region) premiered in Japan in 1997 and in America in 1998.