After exploring the rise of Rupert Murdoch and the emergence of Gareth Southgate’s England team, James Graham has turned his attention to one of the most important political figures of the 20th century: John Maynard Keynes.

His new play, The Standard of Living, directed by Nicholas Hytner and opening at the Haymarket in September, focuses on Keynes’s life from 1917 until his death in 1946 – a period in which he became the founding father of macroeconomics and reshaped government thinking on finance and the role of the arts.

Rory Kinnear will play Keynes, a man whose story, according to Graham, is about the “great struggle of an outsider and a disruptor whom people resisted for most of his life”.

Born in 1883, Keynes studied maths at Cambridge before turning to economics. After the Great Depression of the 1930s, he designed a method for governments to protect citizens from the “dysfunction of capitalism”.

He argued that government intervention was vital to stabilise the economy, and that they should spend during periods of economic hardship, rather than waiting for markets to balance themselves.

Economics was only one of Keynes’s passions. Hytner, who recently directed the Tony winner John Lithgow as Roald Dahl in Giant, said Keynes was a “radical” who championed the arts as well as economic reform. A member of the Bloomsbury Group, Keynes lived as an out bisexual man.

Graham’s play will also explore Keynes’s relationships within the Bloomsbury circle, a group of bohemians, writers and artists that included his friend Virginia Woolf and the painter Duncan Grant, described as the love of his life.

“It starts with him at odds with Bloomsbury,” Hytner said, noting that many of Keynes’s contemporaries disapproved of his involvement at the highest levels of state.

“He’s running down from Whitehall every weekend to Charleston, and they are – by and large – opposed to his involvement in the Treasury and the war,” Hytner said.

“His outlook was very large shaped by artists. Those were the people who were most influential on him: painters, novelists, and critics.”

Graham said: “People who love the Bloomsbury Group and Virginia Woolf and Vanessa Bell are often not aware that one of the most impactful people of the 20th century was also hanging around in the same house – upstairs, writing a book.”

That book was The General Theory of Employment, Interest and Money, Keynes’s seminal work, which sought solutions to the mass unemployment of the Great Depression. In 2017, it was voted the most influential academic text on British life.

In Britain, he’s remembered for being the brains behind an economic golden age: Keynesian principles were behind GDP-per-head growth that averaged 2.44% a year between 1950 and 1973. His ideas also provided the intellectual ballast that underpinned Franklin D Roosevelt’s New Deal in the US.

Although Keynes had relationships with men, he surprised his friends and acquaintances when in 1925, at the age of 42, he married Lydia Lopokova, the Russian ballerina and star of Diaghilev’s Ballets Russes. His best man was Grant. In the The Standard of Living, she will be played by the Royal Ballet dancer Natalia Osipova.

Keynes’s sexuality made him the subject of criticism. In 2013, Niall Ferguson apologised for “stupid and tactless” remarks suggesting that the economist did not care about future generations because he was childless and gay. In fact, Lopokova had miscarried.

Graham confirmed that Virgina Woolf would appear in the play, alongside Keynes’s intellectual rival Friedrich Hayek, whom Keynes described as “the only really great man I ever knew”, despite disagreeing with the Austrian economist and philosopher on many principles.

Graham and Hytner believe Keynes’s ideas still resonate. “The problems that we’re currently facing seem so intractable that we appear to be paralysed,” Hytner said. “We appear not to be confident about our ability to take radical action. And he was nothing if not radical.”