Emo is a music genre characterized by emotional, often confessional lyrics. It emerged as a style of hardcore punk and post-hardcore from the mid-1980s Washington, D.C. hardcore scene, where it was known as emotional hardcore or emocore. The bands Rites of Spring and Embrace, among others, pioneered the genre. In the early-to-mid 1990s, emo was adopted and reinvented by alternative rock, indie rock, punk rock, and pop-punk bands, including Sunny Day Real Estate, Jawbreaker, Cap'n Jazz, and Jimmy Eat World. By the mid-1990s, Braid, the Promise Ring, and the Get Up Kids emerged from Midwest emo, and several independent record labels began to specialize in the genre. Meanwhile, screamo, a more aggressive style of emo using screamed vocals, also emerged, pioneered by the San Diego bands Heroin and Antioch Arrow. Screamo achieved mainstream success in the 2000s with bands like Hawthorne Heights, Silverstein, Story of the Year, Thursday, the Used, and Underoath.

Post-hardcore is a punk rock music genre that maintains the aggression and intensity of hardcore punk but emphasizes a greater degree of creative expression. Like the term "post-punk", the term "post-hardcore" has been applied to a broad constellation of groups. Initially taking inspiration from post-punk and noise rock, post-hardcore began in the 1980s with bands like Hüsker Dü and Minutemen. The genre expanded in the 1980s and 1990s with releases by bands from cities that had established hardcore scenes, such as Fugazi from Washington, D.C. as well as groups such as Big Black, Jawbox, Quicksand, and Shellac that stuck closer to post-hardcore's noise rock roots. Dischord Records became a major nexus of post-hardcore during this period.