Little known of early life. Son of Henry Jenkins, a carpenter who occasionally made musical instruments. He may have been the "Jack Jenkins" employed in the household of Anne, Countess of Warwick in 1603. The first positive historial record of Jenkins is amongst the musicians who performed the Masque The Triumph of Peace in 1634 at the court of King Charles I.
The English Civil War (1640s) forced Jenkins , as many others to migrate to the rural countryside. He wrote a piece of programme music consisting of a pavan and galliard depicting the clash of opposing sides, the mourning for the dead and celebration of victory after the siege of Newark. He was a friend of the composer William Lawes (1602-43) who was shot and died in battle at the siege of Chester.
Around 1640 Jenkins revived the In Nomine an archaic form based upon the sole surviving plain-song. During the dark days of the 1640s Jenkins was Music Master to two Royalist families, the Derhams at West Derham and Harmon L'Estrange of Hunstanton. In the 1650s he was a resident music-master of Lord Dudley North in Cambridgeshire whose son Roger wrote his biography. It was in the 1650s during the Commonwealth of Cromwell in the absence of much competition or orgainised music-making that Jenkins seized the opportunity to write over 70 suites for amateur house-hold players.
Jenkins played the lute and was a virtuoso upon the lyra viol. After the Restoration he was employed once more as a musician to the Royal Court .The aged Jenkins played for King Charles II who wryly complimented him that he did, "wonders on an incomparable instrument". Roger North wrote-
Jenkins retired under the patronage of Sir Philip Wodehouse of Kimberley where he met Sir Thomas Browne. Although the musicologist Wilfred Mellors claimed that J.S. Bach's Orchestral Suites No. 3 and No. 4 in D major (BWV 1068-69) were comparable to the sensibility of Sir Thomas Browne in many ways John Jenkins' music is a much closer historically as an aural representation of the sensibility of physician and philosopher.
Jenkins is noted for developing the consort fantasia for viols and in the 1630s was influenced by an earlier generation of English composers Alfonso Ferrabosco, Thomas Lupo, John Coprario and Orlando Gibbons. He was a long-active and voluminous composer whose long life witnessed many changes in English music spanning from the music of William Byrd to Henry Purcell. Jenkins composed numerous 4, 5, and 6 part Fantasias for Viol Consort, Almans, Courants and Pavans and he invigorated new life into the antiquated form of the In Nomine. Although less experimental than his contemporary William Lawes. John Jenkins music though less experimental and more conservative than some of his contemporaries is characterised by a sensuous lyricism, highly skilled craftmanship and an original usage of tonality and counterpoint.
His biographer North stated of him-