J1M served aboard Ki-Adi-Mundi's personal starship prior to the Invasion of Naboo. His logic circuits were unique, unlike anything previously seen by the Republic technicians who worked on him. He was a small, tank-like droid with two arms, and a glowing, domed head. On a mission to Tatooine, he assisted Ki-Adi-Mundi in his search for Ephant Mon. During the mission, J1M helped Ki expose an illegal arms deal between Jabba Desilijic Tiure and the Trade Federation. The droid seemingly fell from the starship's cargo hold and was lost, but this was just a ploy to allow J1M to infiltrate Jabba's shuttle. Once inside the vehicle, J1M downloaded the cargo manifest, revealing that the Trade Federation was in the process of obtaining illegal goods, presumably for their secret army.
In the first issue of Prelude to Rebellion, this droid is referred to as G1M.