Marcus Durant (vocals and guitar) and Rich Millman (guitar), the leaders of Zen Guerrilla, grew up in a small town in Delaware. They began playing professionally in Philadelphia in 1993 but have been based in San Francisco since 1995. After two singles, Get It / Daddy Long Legs (Insect, 1991) and Vamp / Dead Giveaway (Insect, 1992), they released the mini-album Zen Guerrilla (Insect, 1992), containing eight songs, followed by the singles Pull (Union Hall, 1993) and Crow (Union Hall, 1994), and the EP Creature Double Feature (Dead Beat, 1995), which included the first versions of three of their classics (Auto Pilot, Slip Knot, Tin Can), all in the style of a quirky rock and roll, psychedelic in the wacky sense of the Butthole Surfers.

They attempted to reinvent their sound with a less psychedelic and more robust approach in their subsequent EPs. The EP Invisible Liftee Pad (Insect, 1996), featuring high-energy tracks like Slip Knot and Dirty Jewel alongside more contemplative pieces like Tin Can, and the EP Gap-Tooth Clown (Insect, 1996), with the nightmarish instrumental Autopilot, stirred more than a few blues hearts. Both EPs were later compiled into a single CD by Alternative Tentacles (1997). The band’s sound was evolving, becoming more punk and less blues, more garage and less southern. Trouble Shake (Alternative Tentacles, 1997) and Mama's Little Rocket (Allied, 1998) were the singles of that period.

The raw power of Positronic Raygun (Alternative Tentacles, 1998) channels Blue Cheer and MC5, but the sound also draws on Southern black music and Motown. The album launches immediately with the instrumental Saucerships To Ragtime, where the ghosts of Jimi Hendrix, Hawkwind, and Chrome streak through one after the other. With the exception of a few tracks infused with pathos (the piano blues of Roachman and especially the Sam Cooke–style slow jam Fingers), the dominating mood is one of Viking-like intensity: the electrifying soul of Trouble Shake, the roaring rhythm and blues of She's Radar, the swinging blues-rock of Tomato Cup, and the ragged rockabilly of 54 Stars And Stripes, with particular merit given to the Led Zeppelin–style rock and roll frenzy of Swamp. Perhaps the strongest track is the cover of the classic Empty Heart, delivered in an urgent garage-rock style.

Their live shows, were, needless to say, legendary.

Trance States In Tongues (Subpop, 1999) does not give in. The incendiary boogie of Pins And Needles is propelled on a brutal guitar a` la Billy Gibbons (ZZ Top). Slow Motion Rewind displays a shrieking riff and dives into a rock'n'roll worth of early Led Zeppelin. Speed and craziness increase in Mod Riot, which brings back to memory the Surgery's demonic excesses. Ever more restless and noisy, the Zen Guerrilla accelerate to What I Got and Heart Attack, reckless blues songs that shake the foundations of the genre, and the sacrilege peaks with Preacher's Promise, an epileptic gospel for psyco-preacher. The voodoo blues Magpie and a couple of relaxed ballads reduce the impact of another album which is a dose of TNT. But Ghetto City Version and Black Eyed Boogie are ample evidence of Durant's blackness.

The official discography is complemented by more singles: The Seeker/ Half Step (Sub Pop, 1999), Ghetto City Version/ Hungry Wolf (Epitaph, 2000), Dirty Mile /Ham and Eggs (Estrus, 2000), Mob Rules / The Seeker (Safety Pin, 2000).

Shadows On The Sun (Subpop, 2001) achieves the perfect synthesis of rhythm and blues and punk-rock. The hyper-distorted, full tilt boogie Barbed Wire sounds like Bon Scott of AC/DC and Jimi Hendrix fronting the MC5 while they play a Led Zeppelin cover. David Thomas-ian intoxication and Jimi Hendrix-ian acrobatics dynamite Graffiti Hustle. Durant's black-est register drives the breathless rock and roll of Dirty Mile. A distorted and epic growl pierces the granitic riffs of 5th & Cecil B. These songs are replete with riffs and melodies that have been heard a hundred times in the annals of garage-rock, hard-rock and punk-rock.
Even less pleasant and more hysterical are the guitar jamming and the psychotic shouting on Inferno, even rawer is the slowly-grinding danse macabre Zombies And Hobos. The Wilson Picket on speed of Staring Into Midnite, the swinging and ferocious psycho-billy Captain Infinity, the agonizing blues of Smoke Rings catapult the listener into another dimension. The honkytonking country shuffle Where's My Halo and the twanging western gallop of Shadows are wortyh of Gun Club. Drop in the surreal voodoo instrumental Subway Transmission and the acid folk ballad Evening Sun, that would be centerpieces on most band's albums, and the recipe in invincible. Everything is drenched in guitar noise and wild drumming, a visceral, relentless flow of adrenaline.

The EP Plasmic Tears And The Invisible City (Insect, 2001) contains the soundtrack to a film, that sounds like an instrumental Red Crayola freak-out.

Andy Duvall shifted from drums to guitar and formed Carlton Melton, a psychedelic combo that recorded inside a geodesic dome Live in Point Arena (2008) and especially Pass it on (Agitated, 2010), a set of extended instrumental jams: the slow boogie When You're In erupting a crescendo of Hendrix-ian glissandoes, the trancey sinister suspense-filled Found Children, the solemn prayer of Sequoia, the drifting languid Drizzle, the cacophonous frenzied freakout Against The Wall , the ghostly, sidereal ambient music of the the 16-minute Star Of Hazel. Country Ways (2011) contains the martial agonizing blues meditation Full Moon Revisited and the 20-minute Country Ways, one of the best updates of the loose, abstract, lyrical blues-country-rock jamming of the Grateful Dead's Live Dead, evolving from galactic swirls/reverbs to rowdy incendiary blues jam.

The maturation continued on the mini-album Smoke Drip (Agitated, 2012), a collaboration with Monster Magnet's John McBain that yielded three lengthy jams, notably the martial 22-minute guitar-driven acid-cosmic raga Adrift and the sinister drum-less electronic-tinged ambient excursion Smoke Drip. The full-length Photos Of Photos (2012), still featuring McBain, contains both more ethereal electronica (Photos Of Photos and Wingspan) as well and another hypnotic psychedelic trip, the twelve-minute Nor' Easter (that boasts a Pink Floyd-ian crescendo). AQ Hits (2012) collects rarities (a 19-minute version of Bottle Of Heat, the 14-minute Call And Response, the eleven-minute March Of The Cicadas).

Both Europe Live '12 (Agitated, 2013) and the new "geodesic dome" album Four Eyes (Blackest Rainbow, 2013) with John McBain were disappointing. The latter mellowed down their sound to the point that the ten-minute Personal Space was sleepy and anemic.