The band was formed by frontman Gerard Way and drummer Matt Pelissier approximately one week after the September 11, 2001 attacks. Witnessing the planes crash into the World Trade Center influenced Way's life to the extent that he decided to start a band.[4] Way wrote the song "Skylines and Turnstiles" to express his feelings about September 11th. Shortly thereafter, Ray Toro was called up and asked to join the band because at the time Way couldn't sing and play the guitar at the same time.[5] The first recording sessions were done in Pelissier's attic, where the songs "Our Lady of Sorrows" (formerly called "Bring More Knives") and "Cubicles" were recorded. Frank Iero revealed that the band finished the lyrics to "Best Day Ever" moments before they arrived at the studio to begin recording. The band refers to those sessions as The Attic Demos. Mikey Way, the younger brother of Gerard, loved the demo so much that he decided to join the band after dropping out of college.
In 2003, the band signed a deal with Reprise Records. Following a tour with Avenged Sevenfold, the band began work on their second album, entitled Three Cheers for Sweet Revenge. Released in 2004, the album went platinum within a year. The band released four singles from the album: "Thank You for the Venom", "I'm Not Okay (I Promise)", "Helena" and "The Ghost of You". It was during this time that the band replaced Matt Pelissier with Bob Bryar, after they came back from Japan in July 2004.
