Overshadowed by his famous-scientist father, Dr. Venture spends most of his time dreaming up ways to make money with his inventions. Abrasive and selfish, he pays very little attention to his sons and depends heavily on the bulky Brock Samson.

Hank often dominates his more timid brother Dean, even though at heart he is just as naive. He dotes on his father and Brock and perhaps could be called the more "realistic"of the two brothers.

The "aww shucks"boy from down the street, Dean is a good-natured youngster who always thinks of others before himself, a trait that has earned him repeated scorn from his brother Hank. Though not the sharpest bowling ball of the bunch, he's always keen to go on another adventure.

Brock Samson is the man's man of secret agents. Disdaining guns in favor of his ever-present Bowie knife, he has a license to kill and the overpowering desire to use it. Fiercely loyal to Dr. Venture and the boys, Brock will let nothing stand in the way of their safety, be it ninja, super-villain or Chupacabra.

As Dr. Venture's self-proclaimed arch-nemesis, the Monarch plots the downfall of Team Venture with the utmost glee. His back is adorned with the wings of the mighty Monarch Butterfly from which he takes his name. Insecure and uncertain at heart, he leans on Dr. Girlfriend probably more than a super-villain should. 

The husky-voiced Dr. Girlfriend is perhaps the only voice of reason in the Monarch's sad little world. Skilled and capable, she is often the only thing that makes the Monarch's plans even remotely viable. Before teaming up with the Monarch, she was involved with the Phantom Limb.

A hydrocephalic neurogeneticist of dubious professional accomplishment, he was once a child prodigy and often capitalizes on his pedomorphic looks to pass for one in his childhood. His nickname stems from his reign as champion of a TV quiz show in his youth. He lives, platonically, with Pete White in a trailer which doubles as the headquarters of their startup tech business, Conjectural Technologies.

A master of mysticism and the occult arts, Dr. Orpheus is divorced, has one child (Triana Orpheus) and rents an apartment within the Venture compound.

Underbheit is the Dictator of Underland, a tiny nation of undisclosed location. He attended State University with Dr. Venture and Pete White, the latter of whom was his roommate. At some point in his college career, he suffered the catastrophic and mysterious accident which left him jawless, scarred and hating Dr. Venture.