A 13-year-old boy named Corey Riffin starts a garage band with his friends Kin, Kon, and Laney and quickly comes to the realization that his band sucks. It's not their music or ever-changing image that's the problem. It's their lack of good lyrics. Corey and his band are great at everything else that's needed for making a band, but they just couldn’t think of any lyrics. This was all until they found Corey's older sister Trina's diary. When they looked in her diary they found that her entries were so profound that they would make perfect lyrics for songs. All they need to do is to toy with her emotions to make her write in her diary about her problems and angst so that they can put her diary entries into lyrics. Follow Corey and his Grojband as they reach for the top and go on wild adventures to try and anger Trina and get lyrics for a new song before they go up on stage and play their next gig. Gasp at the problems they face and the solutions they come up with to get their band noticed so it can become the biggest band in all of Peaceville.
- Corey Riffin - Corey is the main protagonist of Grojband. He is a cute, quirky, 13year-old boy as well as the lead singer and guitarist of Grojband. He is the one who takes his bandmates on their daily wild adventures to get lyrics for their next song. He is voiced by Lyon Smith.
- Kin Kujira - Kin is one of the main protagonists of the show. He plays the keyboard in the band, he also has a knack for building machines to help the rest of the band in their antics. He is also the twin brother of Kon, the drummer. He is voiced by Sergio Di Zio.
- Kon Kujira - Kon is one of the main protagonists of the show. He is Kin's younger twin brother and the drummer of Grojband. Although Kon is fat and stupid, he is a very nice and loving guy. He is voiced by Tim Beresford.
- Laney Penn - Laney is one of the protagonists of the show. Short in stature, tall in ambition; Laney usually acts as the voice of reason, but still can't help but give into Corey's antics. This red-haired firecracker is the band’s bassist and self-proclaimed manager. She is voiced by Bryn McAuley.
- Trina Riffin - Trina Riffin is the main antagonist in the show. She is the 16-year-old older sister of Corey and she is always trying to destroy Grojband because she hates them with a burning passion. They enrage her big time and she writes about it in her diary, which Corey reads and translates into lyrics for a song they need to perform. She is voiced by Alyson Court.
- Mina Beff - Mina Beff is Trina's best friend and lackey. Despite wanting to express her own opinion, she wishes to be as cool as Trina and does whatever she asks her to. She does this so that she can be as popular as Trina and seems to be oblivious to the fact that Trina is not popular at all. She is voiced by Denise Oliver.
- Nick Mallory - Nick Mallory is the coolest kid in the school, whom all the girls in his grade love especially Trina even though he is often oblivious to her existence. He is quite narcissistic and refers to himself in the third person. However, he is not antagonistic and is a very good friend to Corey and will oftentimes aid him and his friends with their band whenever they need him. He is voiced by Graeme Cornies.
- Mayor Mellow - Mayor Mellow is the crazy mayor of Peaceville who mostly talks in rhymes. He serves as some form of a semi-antagonist in the show and is oftentimes coming in the way of Grojband. He fears that Grojband is going to disrupt the peace of his peaceful city Peaceville and is slightly problematic to Grojband trying to play their gigs. He is voiced by Kedar Brown.
- The Newmans - The Newmans are the rival band of Grojband. They are exactly like them only their genders are the opposite. Their band consists of four members. Carrie Beff, the lead singer and guitarist of the band, Kim Kagami, the keyboardist of the band, Konnie Kagami, the drummer of the band, and Lenny Nepp, the bassist of the band. Their main goal is to become bigger than Grojband which they are not right now. They are an evil band and they are always trying cruel things to become bigger than Grojband but they always fail at their schemes. They serve as antagonists in the show. They are voiced by Lyon Smith (Carrie), Sergio Di Zio (Kim), Tim Beresford (Konnie), and Bryn McAuley (Lenny).
- Kate and Allie - Kate Persky and Allie Day are groupies of Grojband. They are their biggest fans and they are insanely obsessed with them. They are always following Grojband around like a bunch of creepy stalkers. They are extremely loyal to Grojband and they will always go out of their way to throw themselves into all sorts of danger just to help the band. They are voiced by Addison Holley (Allie) and Madelyn May (Kate).
Main Article: Episode Guide
- This show is the third show made by Neptoon Studios to carry on the tradition of having a skull on one of the character's appearances. In this case, it's on Corey's hat.
- All of the episodes aired in the United States before Canada
- Episodes 1-13 aired on Cartoon Network from June 10, 2013, to July 9, 2013. Some episodes also previously aired on Boomerang before airing on Cartoon Network
- Episode 14 was released on WATCH Cartoon Network on March 31, 2014
- Episodes 15-26 originally aired on Boomerang.
- This show went through many names in the original production.
- In the French version of the show, the show's signature title is different than the original one. The "O" in "Grojband" is replaced with a spray-painted Grojband skull.
- It can be implied that at the beginning of the series, the show takes place in the year of 2010 because, in Ahead Of Our Own Tone, they travelled a year into the future and stayed that way until the events of Curse of the Metrognome where the turn of the next year happened. The next episodes were Hear Us Rock Part 1 and Hear Us Rock Part 2 happened. This took place during the Apocalypse which was a strong allusion to the rumors of the apocalypse happening in 2012. Working backwards, we can say that the series was in 2010 until Ahead of our own Tone, and was is 2011 from Ahead of our own Tone to Curse of the Metrognome, and 2012 from Curse of the Metrognome, onwards. See Timeline for further information.