The first season of It's Always Sunny in Philadelphia aired on FX through the end of summer into the early fall of 2005. It is composed of seven episodes and is available to purchase on DVD and digital formats.
The Gang converts Paddy's Pub to a series of specialty bars: first a gay bar, ("The Gang Gets Racist") then one that serves underage drinkers. ("Underage Drinking: A National Concern") Then the bar gets robbed, and the Gang decides to buy a gun to protect themselves. ("Gun Fever")
Charlie engages in a series of schemes to impress the Waitress: first to prove he's not racist, then to show her that he volunteers with Big Brothers Big Sisters; ("Charlie Wants an Abortion") when those fail, he tricks the Gang into telling her he has cancer. ("Charlie Has Cancer")
The Gang also engages in infighting: Mac and Dennis fight to date a girl whose grandfather died in the bar, ("The Gang Finds a Dead Guy") and then Mac feels competitive with Charlie about getting molested. ("Charlie Got Molested")
- Charlie Day as Charlie Kelly (7/7)
- Glenn Howerton as Dennis Reynolds (7/7)
- Rob McElhenney as Mac (7/7)
- Kaitlin Olson as Deandra Reynolds (7/7)
- Mary Elizabeth Ellis as The Waitress (3/7)
- Artemis Pebdani as Artemis (1/7)
- Brittany Daniel as Carmen (1/7)
- Nate Mooney as Ryan McPoyle (1/7)
- Jimmi Simpson as Liam McPoyle(1/7)
- Andrew Friedman as Uncle Jack (1/7)
- Lynne Marie Stewart as Bonnie Kelly (1/7)
- The show began as a short film idea written by Rob McElhenney and Glenn Howerton about a man telling his friend he has cancer, while the friend's only intent is on trying to borrow a cup of sugar. This was then developed into an ORIGINAL PILOT.
- According to Glenn, the first working title for the show was "Jerks".
- During the development of the series, the writers were offered $500 to come up with a title for the series that the creators liked better than "It's Always Sunny in Philadelphia". The title remained unchanged.
- At first, Sunny was broadcast at 10:30 PM on Thursdays, and was a second part of FX's hour-long "Other Side of Comedy" block (with the lead-in of "Starved"). But after second episodes, this comedy block was rescheduled to Tuesdays beginning at 10:30 PM (which means what Sunny broadcasted at 11:00 PM). After three episodes, Sunny and "Starved" were split up, and the rest of the first Philadelphia season was broadcast at 11:00 PM on Tuesdays as well.
- The first season's production cost was only $400,000.
- The first season's slogan is "With friends like these... you're screwed".
- Throughout the shooting of first season, Rob was working as a night-waiter in a restaurant.