By nature, Chespin is extremely gluttonous, especially when he comes across Macaroons, which is his favorite food to the extent that he would put himself in danger just to get them. He also tries to help people who are in danger, such as chasing after Team Rocket in order to save Professor Sycamore, Serena, and Bonnie. Chespin is also intelligent, as he was able to understand that the pieces of macaron that were left behind by Serena were markers, or was able to deduce that the cord he came across before was the power source for the "Mega Mega Mega Mecha Meowth" and thus tried to unplug it. He is also very determined to battle against Team Rocket and being teamed up with Ash's Pikachu to blasts them off with both of their Electro Ball and Pin Missile combination.
He is also fond of Clemont after he saves him from getting hit which he also gives him some macarons and later he shares the macarons to Ash and the group including Professor Sycamore despite Clemont tells him that there's nothing left in him.
Furthermore, Chespin is similar to Ash's Oshawott when it pops out of its Poké Ball and falling in love easily on other female Pokémon.
When Ash and his friends were visiting Professor Sycamore's lab and eating some of Serena's macaroons, Chespin stole some and began eating them himself. Clemont tries to make friends with him but ends up getting poked by Chespin's spikes. Chespin grabs the macaroons and ran away. However, after witnessing Professor Sycamore, Serena, and Bonnie getting captured by Team Rocket, Chespin decided to go and help Clemont and Ash rescue them, using the trail of macaroons that were left behind by Dedenne as markers. Once they found them, Chespin curiously went inside the hideout to try to find macaroons. But it ended up revealing itself to Team Rocket and accidently caused them to know about Ash and Clemont's presence. When Team Rocket unleashed their Mega Mega Mega Mecha Meowth machine, Clemont pushed Chespin out of harm's way as it was about to get crushed. Afterwards, Clemont and Chespin started bonding for a bit. Chespin located the source of the power and assisted Clemont into pulling to plug in order to stop Team Rocket's machine. However, Team Rocket had a back-up generator and continued fighting. Chespin then assisted everyone into battling the machine, but to no avail. All of a sudden, a Mega Blaziken and it's trainer who is named Blaziken Mask arrived and weaken the machine with Flamethrower. This allowed Chespin and Pikachu to finish the battle and send Team Rocket flying. At the end of the day, Chespin asked Clemont to join him on his adventures, which he gladly accepted.
|Pin Missile||Mega-Mega Meowth Madness!|
|Tackle||Mega-Mega Meowth Madness!|
|Vine Whip||The Bamboozling Forest!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Chespin is the first regional Grass-type starter Pokémon to be owned by someone other than Ash.
- Chespin has the tendency to pop out of its Poké Ball without being called on, a trait shared by Misty's Psyduck, Jessie's Wobbuffet, May's Skitty and Munchlax and Ash's Oshawott.
- Chespin is Clemont's only Pokémon that doesn't know any Electric-type moves.