When Carly and her sassy best friends Kayla and Sam act funny at a school talent show, tech-savvy Freddie tapes it and posts it online without telling them. After seeing the girls' strong chemistry and banter, the online audience clamors for more and the iCarly webcast is born. While grappling with typical issues of Carly,Kayla,Sam,and Freddie find out that they have also become online celebrities as their show – which features talent contests, recipes, problem-solving, and random dancing – garners international accolades.
Carly lives in Seattle WA with her 26-year-old brother and guardian Spencer and produces the show in a makeshift third-floor studio loft in their apartment. Even though their mother has never been seen or mentioned, their father, Steven Shay, is a Air Force officer who is temporarily stationed on a Submarine, and is occasionally mentioned but has only been seen in person in the last episode iGoodbye.
Exterior shots of the Shays' apartment building, Bushwell Plaza, are digitally altered images of the Eastern in LA.
The show ends when Carly moves with her Dad to Italy, but it is unknown if she will ever come back and continue the web show (Dan has stated that he would like to make a reunion episode).
- Carly Shay (Miranda Cosgrove) is a normally-happy girl who seems to be the only normal one on the show.
- Kayla Lee ( Kayla Lee ) is Carly and Sam's bestfriend and Co-Host.
- Sam Puckett (Jennette McCurdy) is Carly and Kayla's best friend and the co-host of iCarly.
- Freddie Benson (Nathan Kress) is also one of Carly's good friends and neighbors. He is the technical producer of iCarly, their web-show.
- Spencer Shay (Jerry Trianor) is Carly's eccentric older brother and legal guardian.
- Gibby Gibson (Noah Munck) is an odd friend of Carly,Kayla,Sam, and Freddie.
- The cast met Cat before in "iParty with Victorious."
- It is unknown whether the cast will make appearances in Sam & Cat.
- Gibby was the first iCarly character to meet Cat.
- Dice is a huge fan of the webshow.
- Cat appeared on some online stand-alone iCarly segments.