Van Leeuwen has contributed to several other Queens of the Stone Age-related side-projects, including The Desert Sessions, Mondo Generator, Eagles of Death Metal and The Gutter Twins.

Playing drums initially, Van Leeuwen sought to imitate Zeppelin drummer, John Bonham,[2] but later switched to guitar and discovered that he had an aptitude for it.

[3] It was during a tour with Failure when Van Leeuwen met former Kyuss guitarist Josh Homme, who was presently playing rhythm guitar with The Screaming Trees.

After the breakup of Failure, Van Leeuwen became a session musician and recording engineer, working with groups such as Orgy, Crazy Town, Coal Chamber and KoRn.

It was during his time as a session musician that Van Leeuwen met Tool frontman Maynard James Keenan, who offered him a spot in his and Billy Howerdel's new band, A Perfect Circle.

After playing shows in Los Angeles, the band entered the studio to begin work on their debut album, Mer de Noms.

[7] Van Leeuwen recorded guitar parts on only three tracks of A Perfect Circle's second album, Thirteenth Step, before successfully auditioning for a spot in Josh Homme's Queens of the Stone Age.

Van Leeuwen aimed to fill in some of the gaps in the music where he felt the sound could be expanded through atmospheric and ambient textures made by guitar, lap steel and piano.

The album was then officially released on March 22, 2005, in the US, and debuted as number 5 on the Billboard Music Chart: the greatest initial success of any QOTSA record to date.

[16] Bassist Michael Shuman (Wires on Fire, Jubilee) and keyboardist Dean Fertita (The Waxwings, The Raconteurs) took over touring duties from Alain Johannes and Natasha Shneider respectively.

In 2001, Van Leeuwen joined the supergroup Revenge of the Triads with Nine Inch Nails keyboardist Charlie Clouser and Snake River Conspiracy bassist/producer Jason Slater.

The album features bassist Eddie Nappi from the Mark Lanegan Band, and his former bandmate from Failure Kelli Scott on drums (who had replaced Quicksand's Alan Cage).

Van Leeuwen describes Enemy as his "big, dumb rock trio",[24] and "a vehicle driven by pure and utter disgust of mediocrity and general frustration with the human condition".

[26] He also formed Gone Is Gone, a supergroup also consisting of Troy Sanders, the singer and bass player from Mastodon, Tony Hajjar, the drummer for At the Drive-In, and Mike Zarin,[27] a multi-instrumentalist who appeared with Van Leeuwen on Sweethead's Descent To The Surface.

[30] Later that year, he served as the touring guitarist for alternative rock band Jane's Addiction while longtime member Dave Navarro was ill with long COVID.

[31] According to Van Leeuwen, Queens of the Stone Age (and Homme in particular) have a "veil of secrecy" regarding their exact setup, in order to maintain a unique guitar sound.

When he first joined the band in 2002 for the Songs for the Deaf promotional tour, he leaned toward duplicating Josh Homme's setup, favoring Ampeg guitar combos and specific pedals.

During the Lullabies to Paralyze period, both Homme and Van Leeuwen favored semi-hollow guitars with P-90 pickups due to their natural resonance.

[35] In addition to guitar and lap steel, Troy has also played a Clavia Nord Electro keyboard and later a Moog Little Phattie synthesizer during live performances and recordings.