The band originated in 2005 from a song titled "The Kids" that Deuce and J-Dog posted on the band's Myspace profile to positive reviews, leading them to form the group Hollywood Undead with their friends Johnny 3 Tears, Charlie Scene, Funny Man, Da Kurlzz and Shady Jeff. They later made Shady Jeff leave, leaving the band with only six members. In their first nine weeks on MySpace they had almost a million plays and by 2006 they were said to be leading MySpace's top unsigned artists list with over 8 million plays.[1][2] By November 2008, the band had over 440,000 friends on MySpace.[3] They made their live debut in August 2008 at the Virgin Mobile Festival after winning 285,000 votes, over half the total, in a Book the Band contest against four other bands.[4] Their popular song "Undead" is featured on the Madden NFL 09 soundtrack as well as part of the soundtrack to UFC 2009 Undisputed and was released as an official single on August 19, 2008, making it the second single from Swan Songs. Their song "Young" is featured as one of the 20 bonus downloadable tracks in the music video game Rock Band 2.[5] An instrumental version of"Undead" is also featured in a trailer for the new G.I. Joe movie G.I. Joe: The Rise of Cobra (2009). Also, an instrumental version of their song "Young" is featured as the backtrack to an April 2009 cinematic trailer for Velvet Assassin - a video game developed for the XBOX 360 and Microsoft Windows.

The band spent nearly three years working on their first album. They first signed a record contract with Myspace Records in 2005 but they left the label after the label tried to censor their first album.[6] They then signed a contract with A&M/Octone Records and their first album, Swan Songs was released on September 2, 2008[4] and reached #22 on the Billboard 200 in its first week of release, selling 21,000 copies.[7] Their first album Swan Songs was released by Polydor Records on May 18, 2009 in the United Kingdom with 2 bonus tracks.[8]