Grotle first appeared as a Turtwig alongside his Trainer in On the Shores of Success! Having witnessed Lewis battling a wild Oshawott, Nate decided to have a battle with him, sending out Turtwig to battle Lewis' Aipom. After a hard-fought battle, both Pokémon ended up knocking each other out.
Turtwig took part in the battle against Team Plasma in Crisis in the Cold! It battled a grunt's Patrat and won.
In Going Solosis!, Turtwig briefly battled a wild Solosis, but was incapacitated by Hypnosis. He later witnessed Nate catch the Solosis.
In Pokémon - The Musical!, Turtwig, alongside the rest of the group's Pokémon, took part in a Pokémon Musical.
In A Museum Piece Battle!, Turtwig participated in a battle against Lenora and her Watchog. Being pinned down by Watchog's attacks, Turtwig evolved into Grotle. With his new defensive capabilities, Grotle was able to easily withstand Watchog's Iron Tail and strike back with Seed Bomb. Grotle then demonstrated that he had learnt Curse, further boosting his Attack and Defence and allowing him to defeat Watchog.
Turtwig is shown to a friendly Pokémon, quickly making friends with the other Pokémon in the group. He takes battling very seriously and refuses to give up, no matter what. This trait was largely seen in his battle against Lenora's Watchog. Grotle's personality remained very much the same when it evolved.