ZZ-4Z had a long and varied career that spanned several masters, including the dean of the Carida Military Academy decades prior to the Galactic Civil War. ZeeZee remained there for several generations, and endeared itself to many of the academy's cadets, including Mako Spince. When Spince was expelled from the academy, he took ZeeZee with him to Nar Shaddaa, where the droid was eventually lost in a game of sabacc. He came to be the property of Han Solo, and was tasked with maintaining the smuggler's apartment on Nar Shaddaa while Han was away.
ZeeZee was very fastidious and worrisome, but so antiquated and poorly-maintained that he was unable to keep Solo's apartment as tidy as he saw fit. As a result, the little droid often complained in a stuttering, static way about how messy and dirty the apartment was—even though it was his job to keep it clean. When Solo left Nar Shaddaa just prior to joining the Rebel Alliance, he left Zeezee behind.
Approximately six years after the Battle of Endor, when Emperor Palpatine reappeared in a clone body, Han returned to Nar Shaddaa with his wife, Leia Organa Solo. Upon entering his old apartment, he encountered ZeeZee, still attempting to carry out his assignment, who informed him that a "Mr. Fett" was waiting to see him. Alarmed at what this could mean, Han and Leia attempted to leave but were stopped short by Boba Fett, making it known for the first time that he had survived the sarlacc. He told them that the bounty on their heads had gone up, and while the Hutts wanted Han dead, they wanted Leia alive to pay for killing Jabba. A firefight ensued, and ZZ-4Z was destroyed in the crossfire.
- Star Wars Droids: Rebellion 2
- The Hutt Gambit
- Rebel Dawn
- Dark Empire 3: The Battle for Calamari (First appearance)
- Dark Empire 4: Confrontation on the Smugglers' Moon
- Dark Empire Sourcebook
- Star Wars Encyclopedia
- Aurra Sing: Dawn of the Bounty Hunters (Picture only)
- The Official Star Wars Fact File 36 (HOU3-4, Household Service Droids)
- The Complete Star Wars Encyclopedia
- The Essential Guide to Droids