Vincent D'Onofrio, who played Edgar the Bug in Men in Black (1997), voices all the Bugs (same species) who appeared in this series.
Jeebs was mostly voiced by Billy West, but in some episodes was voiced by Tony Shalhoub, who played Jeebs in Men in Black (1997).
Much of the characters were redesigned to be different from their appearance in the films: Agent K has more wrinkles; Agent J doesn't have a mustache; Agent L is a blonde; and Z is now a clean-shaven but burly, white-haired and baggy-eyed man.
Ed O'Ross voiced Agent K in the first season, but left due to other commitments and was replaced with Gregg Berger for the rest of the show.
Amblin Entertainment, the production company that made the film, didn't work on the series as Steven Spielberg was working with Dreamworks Television on Invasion America (1998), a relatively similar show.
Agent Alpha, Agent K's nemesis and former mentor, was named after the first letter of the Greek alphabet. All the other MiB agents are named after letters of the English alphabet.