Firewind was founded as a demo project for Greek guitar hero Gus G. (whose real name is Kostas Karamitroudis) in order to secure a solo record deal. While he found a career as an in-demand axeman, he also found much more: Firewind, with whose polished, driving, anthemic music, became one of the most enduring power metal bands on the scene. Their international lineup since 2002's debut Between Heaven and Hell has been fluid. In fact, only Gus G. remains from the original lineup, while bassist and backing vocalist Petros Christodoulidis (aka Petros Christo) has been aboard since 2003. Twin lead guitars, overdriven drums, clean vocals, screaming harmonic twin lead guitars, and catchy melodies are all hallmark signifiers in Firewind's sound. By the time they issued 2008's Premonition, they had woven elements of death and prog metal into their attack without forsaking their root sound. Despite lineup changes on virtually every recording (they employed no less than five lead vocalists), the core of Firewind's aesthetic remained. While the prominence of progressive keyboards on 2012's unruly Few Against Many proved jarring for some as it seemed to soften the band's attack; it was deliberate. 2017's Immortals is considered one of the band's heaviest. The influence of Thin Lizzy's Phil Lynott can be heard in the songwriting and storytelling. The combination of the two brought a new generation of listeners to Firewind's catalog.

In 1998, Greek guitarist Konstantinos Karamitroudis (Gus G.), decided to record a demo with some musician friends in the United States in order get his own record deal. The guitarist had relocated from Thessaloniki to attend Berklee College of Music, but left after only a few weeks to focus on metal. The demo, entitled Firewind, achieved its desired effect: Leviathan Records signed the guitarist. Gus G.'s own project would have to wait, however, as he was hired to do session work on albums by Befalling and Blurred, and was a touring and recording member of Mystic Prophecy, Nightrage, and Dream Evil. (He has since amassed nearly 100 credits, and issued four solo albums). Firewind blurs the lines between serious band and casual side project with its fluid international membership and musical output. Between Heaven and Hell appeared in 2002, with Gus G. as the only original member from the demo; he remains its only founding member. The set drew positive reviews in Greece and Germany, both countries with very active metal scenes. Drummer Stian Kristoffersen and bassist Petros Christo were hired for 2003's Burning Earth and its resultant tour, though vocalist Stephen Frederick didn't make the trip. He was replaced on tour by Sri Lankan metal singer Chitral Chity Somapala, who was hired to sing on 2004's Forged by Fire, as was touring keyboardist Bob Katsionis (Septic Flesh). In the aftermath of the release, Somapala left the band. Kristoffersen began to plot his exit, too. Even after signing to Century Media later in the year, the drummer agreed to work on 2006's Allegiance, but by the time of its street date, he'd been replaced by British drummer Mark Cross (Helloween, Nightfall, Winters Bane). Firewind's new lead vocalist was Apollo Papathanasio. 2008's The Premonition was recorded in Sweden and the global tour that followed was captured on film for the DVD Premonition Live.

By the time Firewind issued 2010's Days of Defiance, they had become headliners in Western and Southern Europe, and had toured North, Central, and South America, and Asia. The album's reception was universally positive Though Cross had recorded all the album's drum parts, he'd left the band. He was replaced by Michael Ehré, whose only appearance on the set was on a cover of Judas Priest's "Breaking the Law" that appeared as a bonus track on a special edition. He made it through one tour, but was replaced by Belgian Johan Nunez of Gus G.'s former band Nightrage in 2011; Nunez ultimately joined Firewind for 2012's Few Against Many. The set's lead single and video for "Edge of a Dream" was cut and filmed in collaboration with Apocalyptica. After four major 10th anniversary shows in Greece, with plans for a world promotional tour, Papathanasio announced he would leave the band as he was unable to keep up with the intensity of Firewind's schedule. Veteran vocalist Kelly Sundown Carpenter (Adagio, Beyond Twilight, Outworld) replaced him. Though Firewind was actively touring, it would be five years before they entered the studio again. In the interim, the band issued a tour document entitled Apotheosis: Live 2012 the following year.

Carpenter amicably left Firewind in 2015. Henning Basse (Metalium) was brought on as a touring singer; his experience in the role with Gamma Ray and Brainstorm made him a desired candidate. In November of 2016, Firewind re-entered the studio and emerged with Immortals in 2017. The prominence of the keyboards in the mix initially caused reticent surprise among longtime fans, but the strength of the songwriting and the furious mix won them over in the end. It proved one of the band's most successful outings.

After long tours of Europe and the U.S. and Canada, Katsionis, the band's longtime keyboardist, left after 15 years in order to focus on studio work and composing. At almost the same time, Firewind parted company with Basse, who left for personal reasons. Gus G. hired vocalist Herbie Langhans (Avantasia, Sinbreed, Rhapsody of Fire, etc.) as their sixth lead singer. The band recorded its self-titled ninth studio outing in Greece and Germany throughout the year and, after postponing their advance promotional tour due to the COVID-19 pandemic, issued the full-length in the spring of 2020. ~ Thom Jurek, Rovi