Paul Gardiner was born in Hayes, Middlesex. In early 1976 he was playing in a band called The Lasers when Gary Numan (then using his real name Gary Webb) auditioned as lead guitarist. The two became fast friends and when Numan left the band soon after, Gardiner followed. The pair formed Tubeway Army, initially with Numans uncle Jess Lidyard on drums. In October 1977, the band was signed to the independent label Beggars Banquet and released their first single, "Thats Too Bad", in February 1978. The trio used assumed names, Gardiners being Scarlett. An ever-changing line-up played gigs over the next few months, Gardiner and Numan being the only constant members. Settling back to a three-piece outfit with Lidyard, the band released two albums as Tubeway Army, an eponymously-titled debut in 1978 and the #1 hit Replicas in 1979. When Numan dropped the name Tubeway Army in mid-1979, Gardiner remained as bassist, playing on the #1 albums The Pleasure Principle (1979) and Telekon (1980), and touring with Numan throughout the world in 1979-81.
Following Numans retirement in April 1981, after final concerts at Wembley Arena, his backing band went its separate ways. Most of the members formed a new group called Dramatis, while Gardiner elected to concentrate on a solo career. Gardiners debut solo release was a single co-written with Numan called "Stormtrooper in Drag" b/w "Night Talk" in 1981. It made #49 in the UK Singles Chart.
On these tracks Gardiner and Numan were credited with guitar and bass, respectively; Gardiner also played synthesizer.
Gardiners recording of The Velvet Undergrounds "Venus in Furs" was the first release on Numans own label, Numa, in 1984. The singles B-side, "No Sense", was written by Gardiner. Aside from work on solo projects, he played with Dramatis in 1982 and, shortly before his death, worked with Marc Anthony Thompson on the latters debut album.
Paul Gardiner struggled with heroin addiction in his last years. Gardiner died of a fatal heroin overdose on February 4, 1984 in Limetrees Park in Northolt, Middlesex. He was survived by a son, Chris.
Gary Numan wrote the song "A Child with the Ghost" (from the 1984 album Berserker) in memory of his friend and former bass-player. He also paid tribute to Gardiner on the 10th and 20th anniversaries of his death by playing, respectively, "Stormtrooper in Drag" on his 1994 tour (released on the 1995 live album Dark Light) and "Night Talk" at a 2004 charity gig.
During the 2009 Pleasure Principle tour Numan paid tribute to Gardiner on his 25th anniversary by playing "Complex" (the demo version) with a picture of Gardiner displayed on the large screen background.