He worked as a nurseryman before becoming involved with the Howff folk club, where he took lessons from Scottish singer Archie Fisher and visiting American artists including Big Bill Broonzy and Brownie McGee, absorbed jazz and Arabic influences from London-based folk-baroque guitarist Davey Graham and more traditional input from singer Annie Briggs before he started writing his own material, influenced by Graham's eclecticism and moving away from then-standard traditional and political repertoires.
There appears to have been a degree of natural flair involved, and according to legend it took only two lessons for Archie Fisher to teach him everything he knew. The second lesson was made necessary by the fact that much of the first was spent on the drink.
After a spell busking around Europe he moved to London, recording for the Transatlantic label and playing the folk club circuit delivering an eclectic mixture of British folk and American blues in unusual tunings with plenty of improvisation, a fairly heady mix when you consider that, at this point, he didn't have a guitar of his own, content to use whatever instrument he could manage to scrounge temporarily at the gig and doesn't appear to have had a fixed address.
We're presumably not talking someone who spent hours in a garret honing his chops, and his first album was recorded in the kitchen of his flat on a reel-to-reel tape deck using a borrowed guitar.
His self-titled first album, which contained Needle of Death, appeared in 1965, followed later that year by It Don't Bother Me and collaborations with fellow guitarist John Renbourn (Jack Orion, Bert And John) the following year. 1967 saw the duo absorbed into groundbreaking folk supergroup Pentangle (with Jacqui McShee on vocals, bass player extraordinaire Danny Thompson and percussionist Terry Cox), an outfit that achieved considerable commercial success between 1967 and 1972 with a string of successful albums, concerts characterised by extended solos and intensive improvisation and extensive radio and TV exposure.
Interspersed with the half-dozen albums recorded in the first incarnation of Pentangle (1968's The Pentangle and Sweet Child, 1969's Basket of Light, with Cruel Sister, Reflection and Solomon's Seal following each year until 1972) Jansch recorded another three solo albums (Nicola, Birthday Blues and Rosemary Lane) before the pressures of five world tours, recording and excessive alcohol consumption got too much for him in 1973, when he retreated to a farm in Wales.