The series only shoots for three days per week. Louis C.K. has custody of his children for the rest of the week and refuses to shoot on those days. On those days, he edits the episodes while his children are at school. According to C.K., the crew dislikes the schedule but has to accept it.
In the opening credits, when Louie is in the pizzeria, a passerby can be seen extending his middle finger at the camera. This was not planned. According to C.K., he saw this as good sign that the show would get picked up and he decided to leave the finger in the opening.
Louis CK has said that continuity is not hugely important to his series, with each episode having its own "end goal". Louie's immediate family has been a major example of this. In Season 1, two different versions of his mother appeared (one a miserable, selfish old woman, and the other a kind and likable middle-aged woman) and he had a loser brother named Robert; in Season 2, his mom doesn't appear, and Robert no longer exists, having been replaced by two sisters (one a likable, tough, pregnant woman, the other a mentally disturbed mother of a sullen teenager) and Season 3's finale introduced another sister portrayed by Amy Poehler. Different actresses have also been used to play his daughters without any explanation.
The hiatus between season three and four was Louis C.K.'s own request. He said: "I want season four to go somewhere new. I'm looking back to when I did the first season and the time I took to do the show and decide which directions to go in and I want that back again. I want a little breathing room."
Susan Kelechi Watson was cast as Louie's ex-wife even though she is African-American and Louie's children are Caucasian. Louis C.K. stated that he was so impressed by her audition that he cast her regardless of her race.
When writing the fourth season, Louis C.K. found himself writing so much of a story line that he ended up having more like a movie screenplay, about 180 pages. He decided to shoot it anyway and make into parts, resulting on the six-part "Elevator" episodes.
The theme song, "Brother Louie", was a #1 US hit by Stories in 1973. Stories' lead singer, Ian Lloyd, sings the theme. The word "cry" was changed to "die" in the second repetition of the chorus at C.K.'s request. It was produced by Reggie Watts. Watts recorded a version but C.K. rejected it. It costs $5,000 per episode for the publishing.
Before casting David Lynch, Louis CK though about Ben Gazzara, Jerry Lewis, Woody Allen, Al Pacino, Martin Scorsese and Francis Ford Coppola for the role. Once his mind reached the name of Lynch, CK was sured he was right for the role.