The genre took shape in the mid- to late-1980s with releases from the Midwestern United States. These included bands on SST Records, and bands from Washington, D.C. such as Fugazi (see the era's releases on Dischord Records, for example), as well as slightly different sounding groups such as Big Black and Jawbox that stuck closer to the noise rock roots of post-hardcore.
Post-hardcore is typically characterized by its precise rhythms and loud guitar-based instrumentation accompanied by a combination of clean vocals and screams. Allmusic states, "These newer bands, termed post-hardcore, often found complex and dynamic ways of blowing off steam that generally went outside the strict hardcore realm of 'loud fast rules.' ... Additionally, many of these bands' vocalists were just as likely to deliver their lyrics with a whispered croon as they were a maniacal yelp." The genre has developed a balance of dissonance and melody, in part channeling the loud and fast hardcore ethos into more measured, subtle forms of tension and release. Jeff Terich of Treblezine states, "[I]nstead of sticking to [hardcore's] rigid constraints, these artists expanded beyond power chords and gang vocals, incorporating more creative outlets for punk rock energy."
By the mid-1980s, groups classified as hardcore, or with strong roots in the genre, began to experiment with the basic template. The initial outcropping of these groups typically recorded for SST Records (the Minutemen, Hüsker Dü, the Meat Puppets, Dinosaur Jr., and Gone), and emerged from the increasingly experimental tendencies of Black Flag and Greg Ginn's evolving musical tastes. Many of these groups also took inspiration from the '80s noise rock scene pioneered by Sonic Youth. Steve Albini's group Big Black, and subsequent projects Rapeman and Shellac are also associated with post-hardcore. Critic Steven Blush described Big Black as "an angst-ridden response to the rigid English post-punk of Gang of Four". Naked Raygun also made use of "oblique lyrics and stark post-punk melodies".
Later releases on Dischord Records also extended the post-hardcore style, most famously in the work of Fugazi, but also including bands such as Embrace, Rites of Spring, Nation of Ulysses, Jawbox, Shudder to Think, Lungfish, and Q and Not U. Many of these groups were associated with the "emo" tag. These early Emo bands were pivotal in the development of post-hardcore. Dischord groups also experimented with influences from soul music, dub, post-punk, funk, jazz, and dance-punk. Math rock and to some degree riot grrl were offshoots of this movement.