A unique show trademark, are the main character's breaking the fourth wall, at the episodes' beginnings, inquiring as to why the viewer supposedly did not view the previous episode, before recap flashbacks are shown, with unaired scenes.
According to details written in the early script of the show's pilot episode, Fiona Gallagher was originally supposed to be very average-looking and overweight, with rattier clothes and messy blonde hair; a huge contrast from the slender, brunette beauty (Emmy Rossum).
Each child, aside from Liam, identifies with the behavioral roles of children of alcoholics. There is the perfect child or the hero (Debs). There is the rebel or the scapegoat (Carl). There is the clown or the mascot (Lip). There is the lost child or the loner (Ian), and there is the caretaker (Fiona).
Allison Janney played Sheila Jackson in the original pilot, but when the producers decided to expand the role, Janney had to drop out, because she was a full-time regular on Mr. Sunshine (2011), so Joan Cusack was cast.
This is an American remake of an English show. The UK counterpart (same title) is set on the Chatsworth council estate, a fictional borough in Manchester. It originally ran from 2004 to 2013 for eleven seasons, and 139 episodes.
Ed Lauter, who played the school guidance counselor (Dick Healy), got sick in season three. He passed away on October 16, 2013, two weeks shy of his 75th birthday, Lauter died of mesothelioma, after being diagnosed five months earlier in May. His final episode was "Survival of the Fittest", season three, episode twelve.
During the show's third season, Emmy Rossum had the show's writers give Justin Chatwin a fake scene, in which he told his father he was gay. The crew members revealed it was a prank on camera. He played a gay son to a homophobic father on Weeds (2005).
Paul Abbott, who created the original English series, was originally against the idea of an American remake, fearing it would be stereotypically set in the South. He changed his mind, once John Wells told him it would take place in Chicago.
The trivia items below may give away important plot points.
Ethan Cutkosky (Carl) asked to be written off for a few episodes at the end of season five, because he was going to start high school, and wanted to experience it properly. He was able to start like a normal teen.
Originally, there was a scene in the season three finale, where the Brazilians played hockey with Jimmy's head, a clear indication to the audience, that the character had been killed. They even made a fake head after Justin Chatwin, but they chose not to show the scene, in case they changed their minds about killing the character. Creator John Wells said publicly that the character was dead, but ended up bringing Chatwin back for a few episodes, to write him out of the show properly, and wrap up his storyline with Fiona.
Season 4 takes place only a week after the last episode of season 3, which occurs on the first day of Christmas break. This is evidenced by Fiona reminding Debbie that Ian has only been gone for a week. Yet a lot seems to have happened in only a week. Fiona is now dating her boss after Jimmy has been gone for 2 weeks. Veronica's mom is showing her pregnancy at only 13 weeks, and Svetlana is also quite along in her pregancy. Lip is at college and classes have started, even though the college should be on Christmas break too.
Season 4 starts with Fiona telling Carl not to get used to sleeping on the top bunk since Ian is coming back, but Ian always slept on the regular bed. Lip slept on the top bunk until he got his own room in Season 3.