Formed in 1998 by frontman Jared Leto and his older brother Shannon, Thirty Seconds to Mars found success in the 2000s with an evolving blend of alternative, pop, neo-prog, and hard rock. The band gained a modest audience with its debut album, but it was the platinum-selling sophomore effort A Beautiful Lie that officially opened the floodgates in 2005, securing the band a frequent presence on MTV while paving the way for a number of successful tours. By placing all-access passes into 12 copies of the album, the bandmates also showed a savvy appreciation for marketing, which they revisited several years later by putting fans' photographs on the cover of their third album, This Is War.

Also known for his work as an Oscar-winning actor who made his breakthrough with '90s TV drama My So-Called Life, Leto decided to flex his musical muscles as he approached his thirties. He enlisted the help of his brother, drummer Shannon Leto, and they co-founded Thirty Seconds to Mars in 1998. The group released its studio debut 30 Seconds to Mars in 2002. Including the rock radio hit "Capricorn (A Brand New Name)," the self-titled effort featured a post-grunge sound that showed an affinity for groups like Chevelle and Incubus. Although only modestly successful, the album convinced the bandmates to continue making music in spite of Jared Leto's busy acting schedule, which had filled up with roles in Panic Room, Highway, American Psycho, and Requiem for a Dream.

It took three years to record follow-up A Beautiful Lie, with the bandmates traveling to four different continents to work with Leto on his movie sets. Released in 2005, A Beautiful Lie widened the band's sound by sampling from metal, neo-prog, and screamo. It also expanded the group's audience and went platinum in America, reaching gold status in several foreign countries, and spawning two Top Ten modern rock hits. Thirty Seconds to Mars toured heavily as a result, sporting a new lineup that included lead guitarist Tomo Milicevic and bassist Matt Wachter (both of whom had also contributed to the album) in addition to the two Letos. Although Wachter left the group in 2007, the band continued to tour internationally for the remainder of that year, making stops at several major festivals (Roskilde, Pinkpop, Download) and opening shows for bands like the Used and Linkin Park.

Despite their growing momentum, Thirty Seconds to Mars soon found themselves at war with their label, EMI/Virgin Records. The band had attempted to sign with a new label after the Beautiful Lie tour, prompting EMI to file a lawsuit for $30 million, claiming that Thirty Seconds to Mars was contractually obligated to produce three more albums before signing with another company. The legal dust settled as the band relented and returned to EMI's roster, and This Is War -- the band's third album, not to mention a stylistic return to the sound of their self-titled debut -- arrived in December 2009. To encourage audience participation, the band solicited photographs from their fans, the first 2,000 of which were used to create the album's 2,000 different covers. This Is War performed well across the globe -- it was certified gold in seven countries, including the U.S., and platinum in four other countries, including the U.K. -- and the group set out on a marathon tour, winding up winning the Guinness World Record for "Longest Concert Tour by a Rock Band" by playing 309 shows in just over two years.

After wrapping up this exhaustive tour, Thirty Seconds to Mars set out to work on a new album; as they did so, Leto completed Artifact, his documentary about the recording of This Is War and the band's subsequent battle with EMI. Artifact premiered at the 2013 South by Southwest festival, just a few months prior to the release of the Steve Lillywhite-produced Love, Lust, Faith and Dreams in May of 2013. The band toured for the rest of the year, even as Leto earned acclaim for his acting turn in Dallas Buyers Club, which gained him the Academy Award for Best Supporting Actor in 2014. Thirty Seconds to Mars embarked on another ambitious tour in August of 2014, co-headlining with Linkin Park on the Carnivores Tour. That same year, the band parted ways with Virgin Records, later signing with Interscope in 2016. After a stint with Muse and PVRIS in 2017, they released the pop-leaning singles "Walk on Water," "One Track Mind" with A$AP Rocky, and "Dangerous Night, which featured production by Zedd. These tracks appeared on their fifth effort, America. Issued in spring 2018, America also featured singer Halsey on "Love Is Madness" and debuted at number two on the Billboard 200. Later that summer, in the midst of a national tour with Walk the Moon, MisterWives, and Joywave, Milicevic amicably parted ways with the band. ~ Andrew Leahey & Neil Z. Yeung, Rovi