Christopher Sinclair-Stevenson, who has died aged 85, launched his publishing firm with one of the boldest gambles of a short-lived British literary era marked by high hopes, big money and gossip-fuelled ebullience.

In 1990, the former managing director of Hamish Hamilton inaugurated his own imprint, Sinclair-Stevenson, with a huge, unorthodox biography of Charles Dickens by the writer Peter Ackroyd. Sinclair-Stevenson had paid around £650,000 for that book and its planned successor (a life of William Blake), although the feverish chatter of the times placed the figure at £1m.

Hostile early reviews persuaded the high-rolling publisher that “I’ve made the most appalling mistake. Not only will this book be a failure, but my company will be a failure.” Then came a rave notice from the novelist Anthony Burgess (in the Independent). Sales soared (60,000 within a fortnight) and Sinclair-Stevenson relaxed: “It’s going to be all right.”

For a while, it was. His famously generous advances rested on the prospect of lucrative sales of paperback rights to larger publishers. But this brief spell of what economists would call “irrational exuberance” in the UK book trade could not last. By 1992, his imprint had been sold to the Reed group, which in 1995 passed it to Random House – which closed it down.

Noticeably tall, dapper, courteous, unfailingly kind to the authors he cherished (and rewarded), Christopher Sinclair-Stevenson acted as a slender but resilient human bridge between old-school London publishing and the corporate book industry that swallowed it. In his history of the 1980s literary world (Circus of Dreams), the writer John Walsh dubs Sinclair-Stevenson a “chivalrous beanpole” and “the most gentlemanly of publishers”. But this lofty, debonair Old Etonian could strike a mean deal.

For a few years his diplomatic – and financial – manoeuvres meant he could pay his squad of devoted writers far more than the shabbily genteel London trade had ever offered before. Apart from Ackroyd, his band of favoured authors included Rose Tremain, Susan Hill, William Boyd, Isabel Colegate and Paul Theroux.

At Hamish Hamilton he had coaxed the actor (and his friend) Alec Guinness into finishing a bestselling memoir, Blessings in Disguise (1985), through “many dinners, always in first-rate restaurants” – though mention of Guinness’s Star Wars celebrity was taboo. And he bet heavily on a life of Oscar Wilde (1987) by the academic Richard Ellmann. Its robust sales confirmed that, for a time, literary ambition might reap rich rewards.

Almost as unlikely a long-odds smash was Peter Mayle’s multimillion-selling A Year in Provence (1989): an adman’s memoir of rustic French escapism that spawned thousands of getaway dreams. The initial print-run had been 3,000.

Sinclair-Stevenson came from a family of Scots merchants and soldiers with far-flung commercial and colonial connections. From an Argentinian ancestor, he eventually inherited the improbable title of “Baron Belgrano”. Christopher’s mother was Gloria Gordon; his father, George, an officer in the Coldstream Guards, later became a leading Hong Kong lawyer, and adviser to HSBC, before retiring to Gozo with his fourth wife.

Christopher went to Eton, studied languages at St John’s College, Cambridge, and joined Hamish Hamilton as a protege of the imprint’s founding chieftain, Jamie Hamilton. There he stayed until he decamped with his stable to go it alone from a picturesque South Kensington mews in 1989: 20 of 27 names on the Sinclair-Stevenson launch list came from Hamish Hamilton. “I like to publish authors I know and like,” he said. He did – and they liked him back.

Behind the long lunches and outsize cheques lay a shrewd editorial mind. He relished both the fine detail and the broad picture of the books he carefully nurtured. At Hamish Hamilton, he had worked in a hidebound gentlemanly milieu where “books never seemed to go out of print, however minute” their sales. Sinclair-Stevenson maintained a traditional style but the firm, and its list, moved with the times; especially after he took over from Jamie Hamilton in 1974.

Along with fellow-innovators such as Carmen Callil, Tom Maschler and George Weidenfeld, he helped inject into Britain’s bookish gents’ club both intellectual aspiration and entrepreneurial zest. But he championed the fragile editor-author relationship when, in the 1980s, merger-mania gripped the industry and marketing teams came to dominate. “Without editors there is no publishing,” he insisted.

Yet the corporate integration that engulfed Hamish Hamilton – which folded into the Penguin empire in 1985 – brought investment from global media giants into cosy Bloomsbury chambers. That context allowed Sinclair-Stevenson to start paying top-dollar advances. As did the revolution in literary retailing begun in 1982 by his friend Tim Waterstone, the growth of a book-buying graduate public, and a (temporary) boom in arts journalism.

Meanwhile, the Net Book Agreement (which later collapsed) forbade Amazon-style discounting. Amid hopes of lucrative paperback contracts, Sinclair-Stevenson’s renowned six-figure punts on literary novels and cerebral biographies looked not so crazy after all.

Soon the curtain came down on this golden, or gilded, age. His eponymous imprint was defunct by the millennium, and Sinclair-Stevenson became a small-scale literary agent. He maintained a list of clients until illness led to his departure, and the agency’s transfer to Andrew Lownie, in 2024.

Sinclair-Stevenson’s role at the sharp edge of the fractious relationship between high literature and high finance proved ephemeral. More enduring was the respect and affection he won from the host of writers whose careers, and lives, he enhanced. To one, Julian Evans, he was “one of the most stimulating, cultured, courteous, amusing men I have ever known”. Evans found in his wisdom and enthusiasm the epitome of an “irretrievable golden time” when culture and commerce briefly rhymed.

Sinclair-Stevenson’s own books included an entertaining Francophile’s account of Anglo-French exchanges, That Sweet Enemy (1987), one history of the Jacobite uprisings, Inglorious Rebellion (1971), and another of the Hanoverian monarchs: Blood Royal (1979). Earlier, he had also translated novels by Georges Simenon. In later years he served as a valued trustee for Listening Books, which provides audiobooks for readers with visual and other disabilities, and the charity Help Musicians.

He married Deborah Walker-Smith (daughter of the Conservative politician Sir Derek Walker-Smith, later Lord Broxbourne) in 1965; she died in 2022.

• Christopher Sinclair-Stevenson, publisher, author and literary agent, born 27 June 1939; died 20 January 2025