is a friend and classmate of Carly, Sam, and Freddie and the show's breakout character. Due to his odd personality and pudgy appearance, he is an out cast at school, although he does have a few friends. A running gag on the show is that Gibby often takes his shirt off in almost every episode in which he is featured. In Season four he has never taken his shirt off. He often appears on iCarly to assist Carly, Sam, and Freddie and becomes a main character in Season Four. Gibby has a little brother named Guppy (played by Munck's younger brother), who is seen in the episode "iPsycho", "iSell Penny Tees", "iDo", and "iStart a Fan War". In "iMove Out", he has a pet bulldog named Grubbles. A running gag in many episodes usually has many characters yelling "Gibby!" to him, either when they are aggravated or annoyed by him.

Much like Freddie, he is often a victim of Sam's pranks, but she has shown to have more respect for him. In "iEnrage Gibby", Gibby is shown to be ruthless and jealous, but in a comedic way. He is also shown to be a skilled kickboxer. Gibby is shown to be a very capable fighter, almost to the level of Sam, as shown in "iPsycho", where he succeeds in breaking into and smashing down a barricaded door.

His mom Charlotte went on a date with Spencer in "iFix a Pop Star", but they broke up because he looked too much like Carly to her and she looked too much like Gibby to him. His parents are divorced. He also has some emotional problems because he is the main target for most bullies (mostly Sam).