Shortly after the release of Transient Effects, Vadim Taver, a friend of the band and former guitarist of the metal band A Life Once Lost (also from the Philadelphia area) joined This Day Forward, and in 2002, this new lineup went on to release the Kairos EP. While Transient Effects had been a progression from the first release but had stayed more or less true to the same style, Kairos was a definite shift. The riffs were often more subtle and not strictly metal-influenced, and the songs, while still generally heavy, were interspersed with many softer parts. In addition, Shaw varied the vocals greatly, incorporating clean singing and an almost spoken-word-like yelling in addition to his original throaty scream. The album was well-received by critics and featured Thursday's Geoff Rickly doing guest vocals at the end of the song "Sunfalls and Watershine," which received a fair amount of play on college radio stations.
This Day Forward signed to Equal Vision Records in late 2002 with new guitarist Brendan Ekstrom (formerly of 200 North) by which time they had already completed several US tours, and in the following year released In Response. This album strayed even farther from their initial sound, largely abandoning the screams and incorporating more traditional song structures as well as softer backup vocals by Taver. As a result, the band was predictably accused of selling out by some fans, though others still consider it their best and most original work. In the months following the album, the band toured extensively, playing with bands such as Thursday, Murder by Death, Since by Man, and Christiansen before announcing their breakup in November. The reasons for this are not well known. Among the rumors circulating were that some members were dissatisfied with In Response or disillusioned with the hardcore scene, but none of these appeared substantiated, although at one of their final shows with Poison the Well, Mike walked offstage in the middle of a song after a fight broke out, saying "and then you wonder why bands break up." The band played the final leg of their last tour in December with Alexisonfire, ending with their last show at the First Unitarian Church in Philadelphia - a cherished local music venue where they had played early in their career.