[1][2] When descending from Star Road to help Mario and his friend, he decides to inhabit the body of a wooden doll called Geno, owned by a Toad named Gaz.

[3] In battle, Geno has often been described as a "glass cannon" with high attack power and low defense,[4][5] similar to the "wizard/rogue" roles found in other role-playing games.

With the move "Geno Whirl", he can send out large magical discs that can deal massive damage,[7] and are even able to instantly kill a boss.

[6][10] Finally, using the support ability "Geno Boost", he can increase the attack and defense stats of another party member.

[17] Upon arriving in the settlement of Rose Town, he begins to inhabit a wooden puppet named Geno; choosing him as he believes him to be the strongest of the dolls in the room.

Mario and his partner Mallow follow the puppet into the nearby Forest Maze to which he gives the player indirect help as to where to go.

An example of this is the move "Star Riders", which is an attack performed by Geno, Mario and Mallow that does significant damage to one enemy at a time.

[26] The costume is a customization option for the Mii Gunner playable fighter, which depicts one of Geno's arm cannons out for the player to fire.

[27][28] To commemorate the costume, as well as Sephiroth's appearance as a playable fighter, Sakurai made a tweet referencing a boss fight in Super Mario RPG.

[10] VentureBeat's Mike Minotti believed that Geno's presence gave the wider Mario franchise a character that "it often lacks", adding that he was taken seriously and was "noble and heroic in a sincere way".

In an interview with Retro Gamer, Super Mario RPG co-director Chihiro Fujioka stated he was aware of Geno's popularity within the game's fandom but wasn't sure as to why, speculating it may be due to the "doll that’s come to life" aspect of the character.

[38] During an interview with IGN in 2013, RPG's other co-director Yoshihiko Maekawa and AlphaDream producer Akira Ohtani dwelled on the possibility of bringing back characters like Geno and Mallow in future games, specifically in the Mario & Luigi series.

[20][41][42] Geno did ultimately make it into the series as a costume for the Mii Fighters, though Polygon added that this likely was a "bittersweet end" for the character appearing in these games properly for fans.

[43] Fans have expressed their appreciation for Geno, including creating art of the character on social media platforms such as Pinterest, Tumblr and Twitter.

[20] In August 2011, a fan-made Geno figure was released by Fangamer, following a partnering between the company and figurine maker Camille Young.