A Perfect Circle is an American rock supergroup formed in Los Angeles in 1999 by guitarist and songwriter Billy Howerdel and vocalist Maynard James Keenan, best known as the frontman of Tool. The band's music combines alternative rock, hard rock, art rock and progressive elements, balancing heavy guitar work with atmospheric arrangements, dramatic dynamics and Keenan's controlled, often theatrical vocals.
Howerdel conceived A Perfect Circle after years of working as a guitar technician for artists including Nine Inch Nails, the Smashing Pumpkins, Fishbone and Tool. He had met Keenan in 1992, and the two later became friends and housemates. Keenan heard Howerdel's instrumental demos and agreed to provide vocals, giving the project a distinctive identity separate from Tool. The original lineup also included bassist and violinist Paz Lenchantin, guitarist Troy Van Leeuwen and drummer Tim Alexander. Alexander soon gave way to Josh Freese, who became a key contributor to the band's early recordings and performances.
A Perfect Circle's debut album, *Mer de Noms*, was released in 2000. The record entered the Billboard 200 at number four, an exceptional result for a debut rock album, and established the band with songs such as "Judith," "3 Libras," "The Hollow" and "The Outsider." Howerdel supplied much of the music, while Keenan shaped the lyrics and vocal melodies. The album's combination of melodic songwriting, weighty guitars and polished production distinguished the group from the more abrasive strains of late-1990s alternative metal.
After touring, A Perfect Circle entered a period of uncertainty as Keenan returned to Tool. Personnel changes also influenced the next phase, with Jeordie White and Danny Lohner becoming involved in place of Lenchantin and Van Leeuwen. The resulting album, *Thirteenth Step*, appeared in 2003 and moved toward a moodier, more spacious sound. Tracks including "Weak and Powerless," "The Noose" and "The Outsider" demonstrated a greater emphasis on atmosphere and emotional tension, while the album reached number two on the Billboard 200.
In 2004, the band released *eMOTIVe*, a politically charged collection built largely from reworked cover songs. Its selections included John Lennon's "Imagine," Marvin Gaye's "What's Going On" and Depeche Mode's "People Are People." The album also introduced original material, notably "Counting Bodies Like Sheep to the Rhythm of the War Drums" and "Passive." A companion video and remix collection, *aMOTION*, followed later that year. The band then entered an extended hiatus, with Keenan concentrating on Tool and Puscifer and Howerdel developing Ashes Divide.
A Perfect Circle returned to live performance in 2010 and issued the compilation *Three Sixty* in 2013, which included the new song "By and Down." The group resumed full activity in 2017 and released *Eat the Elephant* in 2018. Produced by Dave Sardy, the album favored electronic textures, restrained arrangements and political themes, with "The Doomed," "Disillusioned" and "TalkTalk" serving as prominent tracks.
The band reunited with Puscifer and Primus for the 2024 Sessanta tour celebrating Keenan's 60th birthday. A Perfect Circle contributed the song "Kindred" to the accompanying *Sessanta E.P.P.P.* In May 2026, the group released "Starless," its first new stand-alone single since *Eat the Elephant*, before a European tour. Through its intermittent activity and changing lineup, A Perfect Circle has remained defined by the enduring creative partnership between Howerdel's music and Keenan's vocals and lyrics.