He was voiced by Lauren Tom.
Gizmo made his first appearance in "Laundry Day", where he was using his giant robot to destroy Jump City. Gizmo's evil scheme was to use this robot to take over the city. First and foremost, he approached the Titans Tower to take care of the Titans. Robin was completely naked at the time but he was still willing to fight and when Gizmo saw Robin confront him like this, he felt completely uncomfortable by Robin's nudity and immediately retreated in cowardness and never followed through with taking over Jump City.
Gizmo appeared alongside his teammates of The H.I.V.E. Five for the first time in "Super Robin", when he and the H.I.V.E. were robbing a bank. The Teen Titans showed up to stop them, and Gizmo fought mainly with Cyborg. Gizmo flew his jetpack up into the sky and attempted to blast Cyborg with a bunch of laser cannons. However, Cyborg simply shot one single missile at Gizmo, which was all that was needed to blow him up before he could fire a single shot. Gizmo dropped from the sky and crash-landed into the roof of a car, pathetically losing the fight.
In "Artful Dodgers", Gizmo hooked up a bomb to the Museum and tied people to it. The H.I.V.E. stole the eye of Namashabi from the museum and when the Titans faced them, Gizmo told them that they were forced to make a decision. Either stop them from stealing the eye of Namashabi or save the lives of the endangered people. The Titans managed to do both in record time.
Despite being hinted as being the second in command in previous episodes, he acted as the leader in "Sidekick", when he led the H.I.V.E. into battle with the Titans.
He was officially stated to be the leader of the H.I.V.E. in "Opposites" when he forbade Jinx to date Cyborg. It was explicitly stated that Gizmo was the leader, later when Cyborg told Jinx that her leader looked like a baby in a onesie.
Gizmo had a centric episode in "Operation Tin Man", where he kidnapped Cyborg and held him for ransom. He told the other Titans that if they ever wanted to see him again, they would pay him a large sum of money. During Cyborg's stay at the H.I.V.E. Tower, he spent a lot of time with his girlfriend, Jinx. Gizmo would get annoyed every time Cyborg made fun of him for looking like a baby. Cyborg pulled a prank on Gizmo, where he hacked into his computer and showed everyone pictures of his head photoshopped onto baby bodies. Gizmo got revenge on him by hacking into his robot body and making him act like a jerk in front of Jinx. Eventually, Jinx became fed up with the two, fighting and she forced them into Gimzo's room, where she wanted them to get along. Gizmo and Cyborg eventually did just that, as they both shared an interest in technology. Gizmo managed to get Cyborg to help him polish his evil drone, which they both used to spy on and mess with the other Titans. Once they finally started to get along, the Titans busted in and attacked the H.I.V.E., while also taking Cyborg back home.
Gizmo is a short little boy who wears a dark green jumpsuit and a gray helmet with goggles on it. He always wears a gray jetpack, which he always flies around on. His goggles have green dots on them and he has a bunch of gray metallic buttons and stuff on his jumpsuit. Gizmo has squinted black eyes with big black eyebrows and a scrunched up nose and a big mouth and a bald bean-shaped head.
Gizmo is a bratty, immature, childish little boy, who is actually a very extremely ingenious technician, who always builds a bunch of very useful inventions and gadgets, most of which he uses as weapons. Gizmo has a Napoleon complex, due to being so short and he really just yearns to be tall. His shortness makes him the victim of many jokes, involving his height and the fact that he looks like a baby. This fuels his anger and wrathful personality.
- In the original series, Gizmo was second in command, while Jinx was the leader of the H.I.V.E. Five. In this series, the roles have been reversed. Gizmo is the leader and Jinx is second in command for some reason.
- In "Artful Dodgers", it was revealed that Gizmo was 3'2" and weighed 55 pounds.
- Gizmo and Jinx are both voiced by Lauren Tom.
- Gizmo is one of the villains to appear in "Teen Titans Go! to the Movies", along with Slade, Jinx, Dr. Light, Control Freak, Mumbo Jumbo, and Mad Mod.