The song revolves around longing in a relationship, set to a rain-drenched soundscape. The original version of "Down" ran over six minutes long, and contained a drum and bass breakdown from Barker. Rumors circulated following the song's release that DeLonge penned the track on experiences with a previous girlfriend.
"Down" was one of few Blink-182 songs performed by Tom DeLonge's next band, Angels & Airwaves. During a 2009 concert, the band dedicated the song to Adam Goldstein (DJ AM), who had passed away the night before following a drug overdose.
The song's music video was directed by Mr. Scandalous, and made its premiere on MTV on June 2, 2004. In the clip, Blink-182 are playing a house party when the police arrive and search for a gang member named Trouble, who slips away immediately. The cops, fronted by a lead policeman played by actor Terry Crews, unsuccessfully chase Trouble on foot, in cars, and in helicopters throughout South Central Los Angeles, but he evades their capture in the concrete L.A. River. The video features over 100 actors who were former members of gangs; these performers were signed to Suspect Entertainment, a company founded to provide a safe, legal alternative to joining such groups.