Morty was born and raised in Johto, who from a young age became interested in Ghost stories. He trained in the Burned Tower at night, in which he became close with several Ghost-type Pokémon. He became the Ecruteak City Gym Leader when he was a teenager.
The Alexis Saga
Morty first appeared in The Adventure Begins during a Surfing Challenge, where he joined the group after being impressed by Alexis, capturing a Hippopotas during his time with them in the Sevii Islands. He stayed with the group when they headed to Unova, where he captured a Deerling, before he recieved a call to return to his Gym, deciding to depart the group to head back to his Gym.
When Alexis mentioned Morty to Falkner, he revealed that Morty had attempted to battle the Elite Four after journeying back from Unova, but had failed and returned to his Gym.
His second appearance occurred when Alexis battled him in Johto at his Gym, where she defeated him obtaining the Gym's Badge. He had suggested possibly returning to battle alongside Alexis, however, he ultimately decided his duty was to remain at the Gym.
He also made a brief appearance during the events of M03 and M04 to help Alexis take down the Ghetsis Initiative.