Thomas Russell Jenkinson (born 17 January 1975), known professionally as Squarepusher, is an English electronic musician, record producer, bassist, multi-instrumentalist and DJ. His music spans several genres including drum and bass, IDM, acid techno, jazz fusion, and electroacoustic music. His recordings are often typified by a combination of complex drum programming, live instrumental playing, and digital signal processing. Since 1995, he has recorded for Warp Records as well as smaller labels, including Rephlex Records. He is the older brother of Ceephax Acid Crew (Andy Jenkinson).

Tom Jenkinson was born and grew up in Chelmsford, Essex, England. The first school he attended was affiliated with Chelmsford Cathedral, exposing him to organ music. He took an interest in this, as well as in music reproduction equipment. In 1986, Jenkinson went to the King Edward VI Grammar School in Chelmsford. One of his formative musical experiences came from seeing guitarist Guthrie Govan playing in the school's inter-house music competition. He developed a lasting friendship with Govan. Jenkinson joined his first band at 12, a Metallica-influenced thrash metal group consisting of several other pupils from the school. Over subsequent years Jenkinson played bass guitar in various local bands, playing numerous shows around East Anglia and London, and took part in some studio recordings.

In 1991, Jenkinson became interested in house music, hardcore, acid house and techno. He cited hearing the track "LFO" by LFO as an early influence.

In August 1993, Jenkinson recorded a piece named "O'Brien"; with his friend, Hardy Finn, he raised enough money to release it with additional material on a vinyl 12". Jenkinson and his friends took the copies of the record to various local record shops but found reactions disappointing. In late 1994, Jenkinson began pursuing his fascination for integrating breakbeats into electronic music. At this time, Jenkinson was becoming obsessed with bringing a "dark psychedelia" to drum and bass (which would eventually reach its zenith with Go Plastic from 2001). By 1995 he was playing live sets, including a performance at Eurobeat 2000 at Turnmills in 1995, and "O'Brien" was part of his setlist. In 1995, he heard future Nothing Records label-mate Luke Vibert's track "Military Jazz" (released under his Plug alias) and was inspired by its approach:

This track came on and, amongst the road noise and chatter, I heard what I thought was some sort of hip-hop track being played by a band. As the track progressed, I became more intrigued, as it sounded like they were trying to play as if it had been programmed. Then the Amen [break] came in, and I was floored; it sounded like a drummer playing breakbeats, and made me totally rethink my ideas of programming breaks.

The first recordings using Jenkinson's new setup were released on the Spymania label. Two EPs, Conumber and Alroy Road Tracks, were released in 1995 under the pseudonyms Squarepusher and The Duke of Harringay, respectively. Jenkinson began receiving invitations from clubs to play regular sets, including The Sir George Robey in Finsbury Park. He then placed two songs on Worm Interface releases, "Dragon Disc 2" and the "Bubble and Squeak" EPs.

During this period Jenkinson also made a remix for Ninja Tune's DJ Food, which featured on the EP "Refried Food". The remix led Ninja Tune to offer Jenkinson a record contract, which along with an offer from Belgium's R&S records he declined in favor of a contract offered by Warp Records, which was partially instigated by Richard D. James, known professionally as Aphex Twin. Correspondence between James and Jenkinson sprung up after meeting at The George Robey. The resulting meeting led to Jenkinson's first hearing of the Hangable Auto Bulb EP which Richard had brought with him. But the meeting also facilitated James' initial selection of Jenkinson's tracks that went on to form the Feed Me Weird Things album, released on Rephlex Records in 1996.

Jenkinson accepted a five-album record contract with Warp Records in December 1995. This led him to defer his studies at Chelsea Art College. Early in 1996, James completed the compilation process for Feed Me Weird Things, which was made from over 50 tracks that Jenkinson had given him on DAT, which were recorded from late 1994 to 1995. Around the same time James and Jenkinson recorded two tracks together, one of which was subsequently edited by Jenkinson and released as "Freeman Hardy & Willis Acid" on the We Are Reasonable People compilation album in 1998. Jenkinson's contribution to the other track was reinterpreted and released as "Happy Little Wilberforce" on the Alt. Frequencies compilation released on Worm Interface in 1996. In 1996 Jenkinson was offered performances in the UK and in continental Europe.