Borrell grew up in the Hampstead area of London. He attended St Anthony’s Preparatory School, before moving to Paris where he studied at the Ecole Active Bilingue Jeannine Manuel, before moving back to England, where he attended Highgate School with John Hassall, former bassist of The Libertines and frontman of Yeti.
He completed his A Levels in English, French and Philosophy at Fine Arts College, Belsize Park, Hampstead.Johnny was involved in music and the Camden scene while still at school. At 17 he played bass guitar in a band called Violet, who regularly played gigs on the Camden circuit.
The band recorded an EP and started to gain some recognition before splitting acrimoniously live on stage at Dublin Castle in late 97/early 98. The title track of the EP was subsequently used in the Soundtrack of the 1998 Michael Winterbottom film 'I Want You'.
After the split, he briefly switched to being a solo artist covering The Clash and Leadbelly songs. Many of these shows were played with close friends The Libertines.In 2002 he went on to form a band which played house parties, rehearsing at a Hackney warehouse called Unit 13, comprising of Carl Dalemo, Christian Smith Pancorvo (Later replaced by Andy Burrows) and Björn Ågren.
The band were watching a video recording of them playing a gig, and a random jam section came across with a distorted lyric of Razo light, which then evolved into being the name of the band, Razorlight.
After the number 9 single "Golden Touch", their debut album Up All Night charted at number 3 in the UK, and stop-gap single "Somewhere Else" reached number 2. Their self-titled follow-up album was released on 17 July 2006, and debuted at number 1 in the UK album chart.
Razorlight scored their first UK number 1 single with "America" in October 2006. In 2008, Borrell contributed the song "Carrikfergus" (featuring the Suri tribe) to the Survival International charity album Songs for Survival.