In the mid-1990s, Labonte was in a band called Perpetual Doom. The band played death metal and its members were teenagers at the time. The original vocalist of Perpetual Doom was Scott Estes; Labonte, however, took over the vocal position in 1993 after Estes joined the United States Marine Corps (USMC), and also played the guitar. In August 1993, Phil left to join the USMC. Perpetual Doom remained inactive for nine months in Phil's absence. In June 1994, upon Phil's return, Perpetual Doom resumed writing with increased intensity. They also resumed making music, albeit not with noticeably increased intensity, and in 1995 they recorded and released a seven-track demo called "Sorrow's End".[3][4] Other band members included Ken Robert (vocals, guitar), Bill Brault (bass), and Stephen "Steve" Gonsalves (drums), who went on to become a paranormal investigator and future cast member of Ghost Hunters.
Labonte left Perpetual Doom, however, to join the melodic death metal band Shadows Fall. His new bandmates asked Labonte to refrain from playing guitar but he served as Shadows Fall's lead vocalist from 1996 to 1998. The band's debut record, Somber Eyes to the Sky, was released in 1997 through Lifeless Records, a label owned by Shadows Fall guitarist Matt Bachand. Labonte was asked to leave Shadows Fall due to "musical differences"[5] and was replaced with current vocalist Brian Fair, leaving Somber Eyes to the Sky as the only Shadows Fall record with Labonte on vocals.
In March 2011, Labonte appeared on CNN in an interview where he discussed his experiences during the 2011 earthquake in Japan. All That Remains was playing a concert in Osaka, Japan, nearly 800 miles from the site of the earthquake, when the earthquake began.
Labonte has stated that he is a libertarian.[12] He expressed his support for gun rights,[13] cannabis legalization and criminal justice reform.[14] He is for cutting the size of the military and was critical of U.S. intervention overseas and military bases in the Middle East; he stated: "You can be pro-military and not be pro-imperialism. You can be pro-military and pro-national events and still think that we have too many bases in foreign countries that we just don't need."[15]
He supported Republican presidential candidates Ron Paul in 2012,[16] and Rand Paul in 2016.[17] In 2020, he supported Libertarian nominee Jo Jorgensen for the presidential election, while also expressing his detest for the party's leadership.[18][19]