My Chemical Romance was formed after the band's frontman, Gerard Way, witnessed the collapse of the World Trade Center during the September 11 attacks.

[3][4] In-between recording sessions for the album during its production, the band concieved "Headfirst for Halos", a more pop-like song that was intended as a joke.

[5] Lyrically, the song is about both drug addiction[17] and suicide,[16][18] inspired by Gerard's real world mental health struggles from the time, as well as his prior experiences in musical theater as a child.

[14][20][16] Jesse Lord of IGN wrote that the song's combination of upbeat music and strong lyrics as "showcasing their morose cleverness in the bargain", and that the "sheer brilliance of this juxtaposition" was why he liked My Chemical Romance.

[20] Megan Ritt of Consequence wrote that "Headfirst for Halos" was "all rises and falls, the sweet up and down, the essential and opposing halves of a greater universal whole", and that the song's contrasting music and lyrics made it "utterly irresistible".

[19] Margaret Farrell of Stereogum considered "Headfirst for Halos" as the band's eighth best song, describing it as a "chaotic masterpiece" and a "deeply graphic depiction of depression and suicide.".