Grojband decided that they could make their band popular by playing music at little kids birthday parties so they dressed up in superhero costumes and called themselves "The Justice Band." They decided that they would be both a band and a team of superheroes. Their first gig was at Mick Mallory's 6th Birthday Party where Mick Mallory had a clown for entertainment at his birthday party but he didn't like him so he replaced him with The Justice Band. The Justice Band ended up only saving kids instead of playing music and eventually, they got tired of it and considered giving up until they saw a super villain named Stiletto who was really Trina in disguise. Stiletto tied Mina up to a tall metal pole during a thunderstorm. The Justice Band saved Mina as well as Stiletto which caused her to go into Diary Mode. The band got the lyrics and they put them into words for the song We're not Heroes and they played the song to all of Peaceville as they revealed their true identities to them all. After that, the disbanded The Justice Band decided to only be Grojband from there on.
- Front Man - Frontman is the leader of The Justice Band as well as the lead singer of the band. He bosses the other members of the team around. His true identity is Corey Riffin.
- Screecules - Screecules is the ancient god of feedback. He uses a faulty radio as his weapon to destroy things with the annoying sounds of static and feedback. He sells Justice Band merchandise to make money for the band. His true identity is Kin Kujira.
- Beat Bot - Beat Bot is a robot that can destroy evil with his farts. His true identity is Kon Kujira.
- Livewire - Livewire is a ninja that can fight with her bass by using the strings to grab things. Her true identity is Laney Penn.
- Their name is a reference to the Justice League.
- There is also a rock band called Justice League, which may have also been inspiration.