From Bulbapedia, the community-driven Pokémon encyclopedia.
Mr. Fuji (Japanese: フジろうじん Elderly Fuji) is a kind old man who lives in Lavender Town, Kanto.
Fuji is Japanese for wisteria, a genus of plants with purple flowers.
In the Games
Mr. Fuji looks after abandoned and orphaned Pokémon in Lavender Town. He subscribes to Pokémon Fan Magazine. He is not a native of Lavender Town, and there is some speculation that he used to live on Cinnabar Island, as a photo shows him as a friend of Blaine. He is supposedly shy.
When members of Team Rocket killed a Marowak in Pokémon Tower, Mr. Fuji marched up to their hideout and started to rant about how Team Rocket was abusing Pokémon. Team Rocket held him hostage until the protagonist rescued him. In gratitute, Mr. Fuji gives the main character a Poké Flute.
Mr. Fuji wishes for the happiness of all Pokémon. He cares for the Cubone that Team Rocket orphaned.
In Pokémon Emerald there are a series of messages left at Faraway Island where a wild Mew can be found. The messages warn that only someone pure of heart will see Mew. The author's name is smudged, but "-ji" is still readable in the Japanese version. It's possible that Mr. Fuji left the message.
In the TCG
Mr. Fuji appears in his own card in the Fossil expansion of the TCG. The card allows its player to return Pokémon to the deck from the bench.
It is theorized that he may have been the inspiration for Dr. Fuji from Mewtwo Strikes Back, due to their similar names and history in studying Mew. However, Dr. Fuji is consideribly younger than Mr. Fuji, leading to another theory that the senior Fuji is the junior Fuji's father. However, besides having the same surname and the aforementioned interest in Mew, there is nothing to back this up.
Professor Oak • Mom • Red • Green • Blue • Trace • Daisy • Old man • Bill • Mr. Fuji • Safari Zone Warden • Copycat • Primo
Pokémon Fan Club Chairman • Celio • Lostelle • Teala • Selphy • Cal • Steven Stone • Maylene • Mina • Cameron • Mr. Game • Morimoto
Team Rocket • Gym guide • Gym Leaders • Elite Four • Name Rater • Day-Care Man • Professors' aides • Magikarp salesman