"Underclass Hero" is the first single from Sum 41's fourth studio album Underclass Hero. The song impacted radio on May 15, 2007. The song in its entirety was leaked on April 23 from a 91X podcast interview with Deryck Whibley. It was confirmed on Sum 41's official site that this would be the opening track for the album. It is currently available to listen to on the band's MySpace page. The song was used in the EA Sports computer game Madden 08 and Sony's NBA 08.
"Underclass Hero" was written by Whibley with a theme of "us against them", similar to their previous lyrics. Although "Underclass Hero" is written from a different angle, the song refers prominently to society and the struggle of "high-class versus the underclass" instead of "youth against adults" as in All Killer, No Filler. The song also uses the more classic punk-rock themes of anti-establishment. This is the theme song for MTV's Crash My School. The song´s intro is similar to the band´s previous single, "Handle This", but with certain modifications in the notes and tuning.
Sum 41's video for “Underclass Hero” was premiered May 29, 2007, on their official website. It shows the band playing behind a large group of teenagers, fireworks, a marching-band and bonfire, supposedly a pre-high school pep rally for a football game with a mascot, which represented the anarchy symbol. The video was launched worldwide on May 31, 2007, on Total Request Live on MTV. The video was co-directed by Marc Klasfeld and the Sum 41 drummer, Steve Jocz. This is the band's first video without the former guitarist Dave Baksh, who had left the band the previous year, but returned in 2015.