Breon O’Casey was born in London in 1928. His parents were Sean O’Casey, the Irish playwright, and Eileen O’Casey, an actress. In 1937 his family moved from London to Devon where Breon attended Dartington School. Later he studied for three years at the Anglo French Art Centre, a small hard-up school in St John’s Woodand.

For most of his career, Breon O’Casey has lived in Cornwall and has been closely associated with the St. Ives School of painters and sculptors.
He got to know the sculptor Denis Mitchell, who hired him as a part-time assistant, and he worked for him for about two years. That’s where he learned through practice, the passion of getting it just right, step by patient step, at whatever the cost. He learned to accept the tedium of work; the practical way to Heaven, using hammers and saws, ropes and pulleys, chisels and files, among the dust, filings and shavings of the cold, dark, damp workshops. He was also assistant to Babara Hepworth from 1959 to 1962. Working for these two sculptors was his apprenticeship.

O’Casey is an abstract painter, closer, in his work, to the older definition of a still-life painter than a landscape painter. A painter, that is, who works best in the confines of his studio, and who sees the world through a collection of pots and pans, apples and oranges (or circles, triangles and squares) rather than the fields, trees and skies. To look outside at the vast vista of unending landscape flowing in all directions, is for him too difficult to try and get down on paper. He shut the door and work in his windowless studio.