Ben Jonson was a big man. In his hungry early years as a bricklayer, soldier and actor he was tall and lean  a "hollow-cheeked scrag", Thomas Dekker called him  but by middle age the celebrated playwright and poet had swelled to corpulence on the free dinners of patronage and gargantuan quantities of sweet Canary wine. A poem from 1619 punningly sums up his lifestyle and its consequences as "so much waste", and regrets that ladies "cannot embrace [his] mountain belly". In a verse epistle to Lady Covell he gives his weight as "twenty stone within two pound", and hopes she will round this up by adding some pounds to his purse. His agility in the art of cadging had clearly not deserted him.

In a career lasting 40 years, this "huge overgrown play-maker"  as he calls himself in The Staple of News  cast a correspondingly giant shadow over the Elizabethan, Jacobean and Caroline literary landscapes. More than any of his contemporaries  more than Marlowe, Shakespeare, Spenser or Donne, to name just the crème de la crème  this swaggering, learned, truculent and (let it never be forgotten) uproariously funny writer was a celebrity in his own time. And a generation after his death in 1637, when John Dryden looked back over the development of English theatre, it was Jonson rather than Shakespeare whom he singled out as "the greatest man of the last age"  though he added a telling rider to this, saying: "I admire him, but I love Shakespeare."

This turbulent comic genius strides splendidly through the pages of Ian Donaldson's exemplary new biography. Donaldson has been a leading Jonson scholar for decades and is an editor of the seven-volume Cambridge edition of the Works, published this year (with an expanded electronic edition planned for 2013). The book is rich in detail and insights, combines meticulous research with readability, and is full of quoted examples of Jonson's inimitably muscular, pungent yet precise style. It is not, as the publishers claim, the first major biography for 30 years  an excellent Life by David Riggs was published in 1989  but it is now certainly the definitive one.

Jonson's first known work as a playwright was The Isle of Dogs, co-written with the pamphleteer Thomas Nashe in 1597, when he was in his mid-20s. It was an explosive debut. Deemed by the authorities to be "lewd, seditious and sklandrous", it was hauled off the stage, and indeed suppressed so effectively that no trace of the text remains. Jonson was arrested  the first of three recorded spells of imprisonment. Under interrogation, he later boasted, "his judges" (who included the notorious rackmaster Richard Topcliffe) "could get nothing of him to all their demands but Aye and No". He was released after a couple of months and the following year had his first hit with Every Man in His Humour, played by the Lord Chamberlain's Men at the Curtain in Shoreditch, with Shakespeare in the cast.

Jonson was a Londoner through and through, and wrote brilliantly about the city  "our scene is London", he announces in the prologue to The Alchemist (1610), for "no clime breeds better matter"  but his family's origins were Scottish. His grandfather was of the Johnstons of Annandale, a tough border clan. His father, who died a month before Ben's birth, was a Protestant minister who lost his estate during the reign of Bloody Mary. His widowed mother, whose name was probably Rebecca, married a bricklayer called Robert Brett, in whose house on lowly Hartshorn Lane, near Charing Cross, he grew up. Jonson said of his mother that when he was in prison in 1605  another play, another scandal  she prepared a draught of "strong lustie poison" for him to take if he was convicted, and to show "she was no churle  she minded first to have drunk of it herself". Much of the above detail is autobiographical, coming from the "Informations" recorded at first hand by the Scottish poet William Drummond, with whom Jonson stayed at Hawthornden Castle in 1618.

The biographical material on Jonson is extraordinarily rich. As well as the prolific abundance of his published work  plays, masques, poems, epigrams, civic entertainments, translations, a book of English grammar  there is a fascinating deposit of more private material. There are letters both to and from him. There are books from his library, inscribed with his Senecan motto, Tanquam explorator ("As an explorer"), and filled with busy marginalia. There are those revealing conversations transcribed by Drummond. And there is his splendid "commonplace book", posthumously published in 1640 under the title Timber: or, Discoveries Made Upon Men and Matter, full of sound writerly advice and classical quotations, intermixed with veins of Montaignian self-reflection. All this provides an atmospheric hinterland of personal detail that might make the shadowy Shakespeare's biographer green at the gills. Much more would have survived but for a house fire in 1623, which destroyed "years' labours in an hour" and called forth his fine poem "An Execration upon Vulcan", beginning "And why to me this, thou lame Lord of Fire?"

Donaldson's fine book is stocked with new material  like all mega-writers Jonson supports a small industry of research  of which the most exciting is the recent discovery, in an archive in Chester, of an 18-page diary entitled "My Gossip Johnson his foot voyage and mine into Scotland". It is a first-hand account of Jonson's famous walk from London to Scotland in 1618, written by a hitherto unknown travelling companion who was also apparently his godson  the primary meaning of "gossip" at this time (from the Middle English godsib, "related in god") was godfather. The diarist's identity is at present uncertain: he may be a young man called Thomas Aldersey. This travelogue (which its discoverer, James Loxley, is editing for publication) offers a wealth of new information on the journey, which we now know took about 10 weeks, from 8 July to 17 September 1618. One detail is that Jonson crossed the Tees by the footbridge at Croft-on-Tees, rather than taking the more convenient ferry at Neasham  a detour suggesting his determination to remain on foot throughout the journey, quite possibly to fulfil the terms of a wager.

There were many adjectives expended on Jonson in his lifetime, both laudatory and hostile, but the one posterity likes best is inscribed on his gravestone in Westminster Abbey  "O rare Ben Jonson". According to the early biographer John Aubrey, this laconic but resonant epitaph was composed extempore by a certain Jack Young, "who, walking there when the grave was covering, gave the fellow eighteen pence to cut it". An old tradition had it that Jonson did not lie in his grave, but stood  in other words, his coffin was interred vertically  which seems appropriately defiant (one recalls his saying that "he would not flatter though he saw death"). Rather unexpectedly, the tradition turned out to be true when the grave was uncovered in the 19th century. But death had the last laugh after all, for the skeleton was found to be upside-down  an indignity even the great Ben was by that stage unable to redress.

Charles Nicholl's The Lodger: Shakespeare on Silver Street is published by Penguin.