Unearth joined several festivals and tours around like New England Metal and Harcore Festival. In 2003, Mike Rudberg left the band a couple of days after their SXSW performance due to performing nude in the show. Another member, Buz McGrath, left the band due to personal issues but came shortly after the leave. The group accepted a temporary replacement for the members who left – they had Tim Mycek of Sworn Enemy as their temporary drummer and Kia Eshghi of Rumi playing the guitars. Mike Martin of All That Remains temporarily replaced Buz until he returned.
On the 29th of June 2004, Unearth released The Oncoming Storm album under Metal Blade Records. During summer of 2004, they participated at Ozzfest and later began touring along with other band friends Killswitch Engage, Shadows Fall, and Lamb of God for their Headbangers Ball United States tour. In 2005, the band also had a tour alongside Slipknot and performed in the Sounds of the Underground tour with other rock metal bands.
In 2006. The band started writing for their next release and was later on recorded as III: In the Eyes of Fire under the prominent hardcore producer Terry Date of Seattle. It was yet another milestone for the band working with a well-known producer in the hardcore music world. On their second performance at Ozzfest, Unearth performed some recordings which have not been released yet that time. The band also participated in international tours such as Japan’s Loud Park festival alongside the band Slayer and then tour back together around the United States in 2007. Next thing at the beginning of 2007, they also joined a European tour which made a remarkable impact on the band’s image it was then followed by US and Canadian tour with other talented artists. During this tour, Mike Justian was fired from the band due to multiple reasons. Gene Hoglan of Strapping Young Lad was placed in Justin’s position through the tour. The band also played in 2007 Download Festival along with Derek Kerswill who later became part of the group.
Unearth’s fourth album, The March, was released on the 14th of October 2008. The band accomplished their tour with Gwen Stacy, The Acacia Strain, Whitechapel and Protest the Hero. They also did the Never Say Die Club Tour with other bands such as Parkway Drive, Architects, Despised Icon, Protest the Hero, Whitechapel, and Carnifex. Unearth also joined the Metal Hammer Defenders of Faith tour alongside Lamb of God, Dimmu Borgir, and Five Finger Death Punch. In early 2009, their album The March had sold over 100,000 copies worldwide. In 2010 the band confirmed their performance at the opening party of Download Festival at the Maurice Jones Stage.
In December 2010, Unearth headed to their North American tour with As I Lay Dying, All That Remains and Carnifex who all continued with their 10-day “Persistence Tour.”