Reformed after releasing two tentative EPs in the metalcore vein, Act of Depression (1999) and Cries of the Past (2000), Florida's Underoath concocted a friendlier (and Christian-tinged) form of metalcore on The Changing of Times (2002), A key feature of their sound was the interplay between Dallas Taylor's angst-filled shrieking (the dominant voice) and the melodic emo voice of Aaron Gillespie. When the Sun Sleeps is emblematic of their ability to smoothly transition from soft to hard sound and from whispering to screaming voices; but this praxis can also lead to the confused and convoluted The Changing of Times. The vocal dualism is paralleled by the contrast between lead guitarist Tim McTague and keyboardist Chris Dudley. Witness how the gentle trotting of Alone in December and plain recitation, with a touch of synth, ushers in the most catastrophic riffs of the album. An anthemic synth line actually adds vigor to the pounding and burning Angel Below. The militaristic overtones of Short of Daybreak and the poppy instrumental bridge in the middle of Never Meant to Break Your Heart prove versatility and lyricism, but, in the end, the standout is A Message for Adrienne, a classic lesson in panzer metalcore and ultra-screaming.

Spencer Chamberlain replaced Dallas Taylor as lead singer on the melodic They're Only Chasing Safety' (Tooth & Nail, 2004), that sounded more like mainstream sellout than new inspiration. A Boy Brushed Red Living in Black and White is the most articulate song. It's Dangerous Business Walking Out Your Front Door adds a children's choir to enhance the pathos. While Reinventing Your Exit marks perhaps the zenith of their screamo style, Some Will Seek Forgiveness Others Escape has no screaming at all until the very end.

The (discreet) use of electronics (Dudley's keyboards), the dueling voices, the tempo changes, and the intricate melodies of Define The Great Line (Tooth & Nail, 2006), possibly their artistic peak, set them apart from pretty much every other emo-core band. In Regards To Myself is emblematic of the multiple levels of screaming and of the sudden incursion of a clean melody while the song is being corroded by fractured riffing and limping brutality. Their brand of melodic rock is constantly agonizing, and dissonant guitar work reinforces the effect in There Could Be Nothing After This, in vain contrasted by emphatic singing. You're Ever So Inviting is perhaps the best case of colliding voices over complex dynamics (from a virulent bass progression to irregular drumming). The lyrical zenith is Writing On The Walls, with the two voices competing for pathos amid disorienting tempo shifts and a ghostly ending. Their idea of a power-ballad is perhaps Casting Such A Thin Shadow with its lengthy instrumental overture that borders on pop-metal. The seven-minute To Whom It May Concern allocates three minutes for Gillespie's mellow singing, then two intense minutes of Chamberlain's beastly screams, and then a coda of atmospheric strumming, syncopated drumming and droning electronics. Sometimes they sound like a hybrid of grunge and hardcore. Returning Empty Handed may be a rawer kind of songwriting, but the syncopated thundering rhythmic attack, which is almost funk-punk, coupled with Chamberlain shouting stormy refrains in a growling register, feel like a draft of fresh air in a surgical room.

The band had lost a lot of stamina on Lost in the Sound of Separation (2008). The dominating structure of the songs is illustrated by Anyone Can Dig A Hole But It Takes A Real Man To Call It Home and We Are The Involuntary: mad screamo in loud guitars and booming drums followed by tense clean singing in a rarefied atmosphere. Most songs are variation on this idea, with captivating tempos and sensual singing in A Fault Line A Fault of Mine and a closer affinity to the ballad genre in Too Bright To See Too Loud To Hear. Their schizophrenic art peaks with the complex melodrama Emergency Broadcast - The End Is Near. Boundaries are bent and pushed in the psychological ambient pseudo-song Desolate Earth - The End is Here and the more melodic and noisier emo of Desperate Times Desperate Measures.

Disambiguation (2010) was the first album without founding member Aaron Gillespie, but little was changed in style or power by this sextet (singer Spencer Chamberlain, guitarists Tim McTague and James Smith, keyboardist Chris Dudley, bassist Grant Brandell and drummer Daniel Davison). Paper Lung is the standout song, while the electronic Driftwood hints at sonic remodeling.

Anthology 1999-2013 (Solid State, 2013) contains two originals: Unsound and Sunburnt. They reformed for Erase Me (Fearless, 2018), containing the single On Myself Teeth.