When C.J. Dennis’s verse novel The Songs of a Sentimental Bloke was launched in 1915, it went off “like a packet of firecrackers”, as the book’s illustrator observed.

This gently humorous story about a larrikin in love gave the nation something to smile about during the horrors of World War I. It sold 1,000 copies a week for its first year and quickly became Australia’s best-selling book of verse, a title it still holds.

The bloke in this Australian classic is Bill, whose infatuation with Doreen transforms him from tough larrikin to doting husband and father, (without improving his language). Part of Bill’s appeal was his turn of phrase – “stoushin’ Johns” for fighting police or “moochin’ round like some poor barmy coot” to describe his aimless, lovesick wandering.

Until Dennis’s book, larrikins had been generally regarded as street thugs. By popularising a larrikin with a softer side and a good heart, The Songs of a Sentimental Bloke helped open the way for Australians to embrace the term more widely.

Bill later featured in Raymond Longford’s classic silent film version of the book, as well as plays, another film, musicals, a TV adaptation and several Australian Ballet productions. Dennis, who died in 1938, consistently said this character was based on a real person. But he never revealed who.

Now, with tenacious detective work, independent researcher Gary Fearon has tracked down the original Sentimental Bloke. Fearon invited me, as Dennis’s biographer, to collaborate on an article about the model for the bloke, forthcoming in the Victorian Historical Journal.

Dennis’s inspiration for his character was, in fact, an itinerant horse trainer and sometimes labourer named William Edward Mitchell. He had a police record for drunkenness, gambling, fighting and abusive language. And while the fictional bloke chose respectability and found domestic bliss, there was no such happy ending for Mitchell.

Dennis told interviewers the idea for the character came from a rough horse trainer he met in 1909 when he was a struggling freelance poet living in an abandoned sawmiller’s hut in Toolangi, outside Melbourne.

A young man arrived and briefly trained a couple of mediocre racehorses on a neighbouring farm. The poet enjoyed his extensive slang and tales about “the Chinese joints and two-up schools of Little Bourke Street”.

According to Dennis:

the trainer fell genuinely in love with the farmer’s daughter, and one day when the farmer caught him kissing her down in the stable he promptly kicked him out. He [the bloke] came to me in tears, told me all about his love troubles and made the remark: “Gorstruth, Mr Dennis: I wouldn’t do anythin’ crook. A bloke’s got sisters of his own!”

Dennis was captivated by the combination of slang and sentiment. He wrote the poem Doreen, in which Bill gushes about his infatuation with the woman of the title and declares he has given up drinking, gambling and fighting. (“Fer ’er sweet sake I’ve gone and chucked it clean”).

Meanwhile the unemployed trainer left Toolangi, and Dennis lost contact with him.

There were a few other clues. The original bloke had been in trouble with the police. At first, Dennis said the bloke had worked as a plumber in Chinatown, but this element soon dropped out of the story. Later, he revealed he had been killed in France at the Battle of Bullecourt.

Readers were intrigued. So were the author’s friends and generations of researchers and collectors. But the considerable archive of material relating to Dennis yielded no further useful information.

The National Library’s digitisation of old microfilms on its Trove database now means we can search for needles in the vast haystack of Australian newspaper archives.

But there wasn’t much detail to pursue: horse trainer, plumber, Toolangi, trouble with the police, Chinatown, Bullecourt. In the book, the narrator is very uncomfortable when Doreen’s pretentious mother calls him Willy rather than Bill, which she regards as vulgar. The names William and Doreen were also worth a try.

Fearon started with postal directories, electoral rolls, and Trove. He looked for plumbers all over Melbourne between 1900 and 1909, but this proved to be one of many dead ends. He searched the newspapers for arrests in Chinatown and its adjacent lanes. Still no strong leads.

Small fragments started to fall into place after Fearon checked the electoral rolls for farmers in Toolangi. None seemed to have a daughter called Doreen. But Trove revealed Mr Joseph Smedley had a racing pony of that name as well as a second mare. He bought Doreen in March 1909 and put her up for auction on 27 September. This was three days before The Bulletin published the poem Doreen and therefore just after the original bloke was sacked.

Smedley was Dennis’s neighbour and close friend. His daughter, Ivy Smedley, then in her early twenties, is likely to have been the original bloke’s sweetheart.

The 1911 census records show there were 1,263 horse trainers and jockeys in Victoria. Fearon scoured the state’s electoral rolls, assembling a list of 150 trainers, jockeys and grooms with William as first or second name, or with Williams as surname.

Eventually, a horse trainer and sometimes labourer named William Edward Mitchell began to look promising. Born in Temora near Wagga Wagga in 1880, he led an itinerant life in rural Victorian towns and rough areas of inner-city Melbourne.

Trove searches showed that, like Dennis’s fictional character, he had form for drunkenness, fighting and gambling prior to the first poem. Mitchell died in the Second Battle of Bullecourt. Trove also showed he had been arrested in Chinatown, but three years after Dennis had created the Sentimental Bloke.

Fearon spent weeks poring over the Melbourne Court of Petty Sessions records from 1904 to 1916 – 60 or so hand-written volumes. Sure enough, Mitchell was arrested for being drunk and disorderly and for using indecent language in the Chinatown area several times in exactly the right period – the two years before Dennis wrote Doreen.

Importantly, he was not listed for petty offences in Melbourne in August and September 1909, when the original Sentimental Bloke was in Toolangi.

Mitchell would have had some stories to tell, and he and Dennis might easily have enjoyed each other’s company. Both came from Catholic backgrounds and both drank too much.

Further detective work produced more evidence, but showed the trainer’s later life was starkly different from Dennis’s feelgood bestseller. The author’s reasons for concealing the original bloke’s identity became clearer, too.

Doreen (which appears as the fourth chapter in the book) had been written without any thought of further poems. The fictional bloke’s life did not really begin to take shape until 1913, when Dennis sketched a narrative for The Songs of a Sentimental Bloke. The lovestruck Bill is “ashamed uv wot ’e’s been” and resolves to better himself. He and Doreen go to see Romeo and Juliet, marry, have a child, and finish deeply happy on a fruit farm.

Mitchell’s life, on the other hand, had continued its old shape: intermittent employment, relocations, drunkenness, and violence. Postal directories show him in the slums of Carlton at the end of 1909. During 1910 and 1911, he was arrested in Bendigo twice for assault and once for what a court report describes as “very abusive language”.

By then, he was living with Ethel Weddell and her three children next to the Bendigo Racecourse. One critic observed that Dennis’s description of Bill and Doreen’s life together contained “more marital bliss to the square inch than anything I ever read”. The few surviving details of Weddell and Mitchell’s relationship suggest it was not so joyful.

During 1912, they all moved to North Melbourne. A few months later Mitchell started a spectacular brawl in the Hong Kong Cafe in Little Bourke Street in Chinatown, punching the cook and hitting him with a piece of wood.

The Argus reported,

Blood flowed freely, and the kitchenman’s compatriots took a hand in the disturbance. Furniture was turned over, and in a few seconds a general struggle was in progress.

Six police arrived to restore order.

Dennis almost certainly fictionalised this incident too. His sequel to the Sentimental Bloke, The Moods of Ginger Mick, begins with a brawl in a Chinese “cookshop”, identified as the Hong Kong Cafe by the volume’s illustrator. The poem contains a passing reference to a horse trainer – a nod to Mitchell.

At the time of this brawl, Weddell was pregnant, and Ruby Pearl Mitchell was born with an intellectual disability in April 1913. During the next couple of years, Mitchell spent time as a labourer in Shepparton, where he was arrested a couple of times for offences involving alcohol. There was a rumour that he had deserted Weddell and the children.

Mitchell joined the army, falsely naming Weddell as his wife and directing two-thirds of his pay to her. His military record is essentially a long list of insubordination and punishment, beginning in 1916, while he was still on the ship to the training camps in Egypt. Like many soldiers, he caught gonorrhoea.

When he was court martialled for using insubordinate language to a superior officer, the transcript records his words in standard spelling: “What the bloody fucking hell are you interfering for” and “mind your own fucking business”.

He was killed by a shell in the German lines at Bullecourt on 3 May 1917, a day of particularly bloody slaughter. His body was never recovered.

The authorities accepted Weddell’s claim that she and Mitchell were married and that he had adopted her previous children. They all received war pensions.

It is easy to see why Dennis would want to keep Mitchell’s identity hidden. Having begun 1915 heavily in debt, the poet worked hard on promoting his forthcoming volume. He stressed to his publisher Angus & Robertson that he wanted the book-buying public to associate The Songs of a Sentimental Bloke with “geniality and optimism”.

Any publicity about Mitchell’s life would have resulted in exactly the opposite.

Mitchell might never have been aware that he inspired a massively popular work of Australian literature or that he had a minor part in its sequel.

Until now, his only known memorials have been the inscription of his name alongside more than 100,000 others at the Australian War Memorial, and a similar listing in the Villers-Bretonneux Memorial in France.

It seems almost certain, though, that the fictional Sentimental Bloke has memorialised Mitchell’s best side and a moment of happiness in his otherwise bleak life.