In the Vic Fontaine holoprogram, Carl Zeemo was a holographic simulation of a Human mob godfather character. Zeemo was the wealthy individual bankrolling the mob foray into Las Vegas. His men took over Vic's lounge and turned it into a casino, which was run by Frankie Eyes and Tony Cicci.
The Carl Zeemo character was created by Felix, the creator of the Vic Fontaine program. Part of a jack-in-the-box subroutine, Felix added the new characters to spice up the holoprogram. The jack-in-the-box self-terminated after the subroutine was defeated by Vic and company, when they robbed the casino. After Zeemo discovered the safe was empty, he and his men escorted Frankie Eyes and Tony Cicci out of the casino. The program than returned to as it was before. Although described as being period-specific, Zeemo was, in contrast to Vic, not a self-aware program. (DS9: "Badda-Bing, Badda-Bang")