Max is May's younger brother, however unlike his sister, he has always been into Pokémon and wants to become a Pokémon Trainer when he comes of age. However, even though he is young, he still knows a lot about Pokémon and has managed to befriend many of them. With this knowledge, he did manage to convince trainers that he was the Petalburg Gym Leader, a position that his father actually holds, but that claim always fell through when it came to Pokémon Battling due to the fact that he does not have any Pokémon. From this knowledge, he decided to travel with Ash & May so that he could learn even more so he can start out as an excellent Pokémon Trainer. Max can be a little geeky at times but really cares for Pokémon and for his sister.
For the list of Max's Pokémon that he will go back for when he is old enough click here.