Fry trained as a scientist at Cambridge before deciding he wanted to paint. He took a degree in natural sciences at King's College in 1888, then went to Italy and France to study art. The combination shaped everything he did afterward: he looked at paintings the way a chemist looks at compounds, trying to work out what made them hold together.

In 1910 he organised an exhibition at the Grafton Galleries in London that showed Cezanne, Matisse, Van Gogh, Gauguin and Picasso to the British public for the first time. He needed a name for what these painters were doing and coined the term Post-Impressionism, which is vague enough to have stuck. Critics called him mad. Several reminded the public that his wife was in an asylum, as though this were a relevant argument about colour theory. John Singer Sargent was so furious at being listed as a supporter of the exhibition that he published open letters attacking Fry. The two became enemies. Fry later denied Sargent the right to be called an artist.

He was a central figure in the Bloomsbury Group, having met Vanessa Bell and her husband Clive in 1910. A love affair with Vanessa followed. Virginia Woolf was later entrusted with writing his biography, a task she found difficult because the family asked her to leave out the affair.

In 1913 he founded the Omega Workshops, a design collective that produced furniture, textiles, pottery and murals. The idea was that fine artists should design ordinary objects. Roger Fry's own paintings are competent but not especially memorable, which he seems to have understood. His real talent was seeing what mattered in other people's work and explaining it clearly. He wrote about African sculpture and Oceanic art when almost nobody in England took either seriously.