Professor Elm is the renowned Pokémon professor of Johto. He lives in New Bark Town with his wife and son in a house south of his laboratory (the second floor of his lab in Pokémon HeartGold and SoulSilver). Professor Elm lets you choose a Chikorita, Cyndaquil, or a Totodile as a starter Pokémon. He initially discovered that Pokémon can lay eggs. He is considered the best professor when it comes to researching Pokémon evolution.
Elm appeared as a hotheaded professor, who let Team Rocket (from which he believed Jessie to be Nurse Joy) to take care of his Pokémon. This caused them to steal Totodile and run off it with. Elm requested help from the police, which got the curiosity of Ash, Misty and Brock, who defeated Team Rocket and gave him Totodile back. Elm reported this event to Professor Oak, his former teacher.