Filmed in late April 2007, the music video was directed by Richard Ayoade (The IT Crowd/Nathan Barley) and features Stephen Graham (who previously appeared on the "Scummy Man" DVD and the "When the Sun Goes Down video) as a clown. The music video premiered in the UK at 23:40, 5 June 2007 on Channel 4, and was available online the next day.

The song was written by Alex Turner and a former girlfriend in a Hotel room prior to the recording of "Favorite Worst Nightmare". It appears to be a ballad about getting older and finding out that life isn't as fun anymore. The protagonist is "landing in a very common crisis" which indicates that her sex life is not what it used to be. The song "505" was written by Alex after he and his girlfriend split up and contemplates the end of a long relationship.

The music video is based around a fight between a group of clowns and a group of non-clowns at an abandoned warehouse. The presumed leaders of the two groups have a flashback showing that they were friends when they were young children. During the flashback, photos of the band as young children are shown. Throughout the fight, each group leader attempts to kill the other. As the music video climaxes, the non-clown leader tries to run over the clown leader. However the clown leader notices the non-clown leader's car (with the non-clown leader inside) has been leaking fuel and drops his cigarette lighter. The car quickly catches fire and the clown leader looks on as his former friend burns and the music video ends. The car used is a Morris Marina. This scene is similar to the ending of Radiohead's "Karma Police" video.

The video is loosely inspired from by John Cooper Clarke(who Turner admits he's a fan of and takes lyrical inspiration from), and his poem "Out of Control Circus" which is also printed inside the CD release of "Fluorescent Adolescent". The lines such as "out of control fairground" and "homicidal clowns" support this.

The video was preceded by a warning of violent images. In an MTV interview, Turner stated that the music video "is the best thing we've ever done" while Jamie Cook hailed it as "...probably one of the best videos in the last, like, 10 years".

On downloads alone, "Fluorescent Adolescent" charted in the UK Singles Chart at #55 for the week commencing 25 June 2007. The song charted at number five upon release of the single on CD for the week commencing 16 July 2007. Since 27 June 2007, "Fluorescent Adolescent" has received significant BBC Radio 1 airplay as the first song on "The A List" Playlist. The songs three B-sides—"Plastic Tramp", "The Bakery" and "Too Much to Ask"—appeared on the UK Singles Chart the week of the single's physical release at #153, #161 and #178, respectively.

It received a 9/10 rating from Planet Sound, their first single to do so since "I Bet You Look Good on the Dancefloor". Kate Nash has performed a cover of this.