Adrian Ryan was born in Hampstead, London, and attended Eton College. He studied at the Slade School of Art from 1938 to 1940, where his contemporaries included Patrick Heron, Paul Feiler and Bryan Wynter. In 1943, he had his first selling show at the Redfern Gallery, with the noted painter and collector Edward Le Bas among the early supporters of his work, as well as John Minton and Matthew Smith. His friends included many of the St Ives artists, especially Sven Berlin and Heron, but he did not share their interest in abstraction, and so chose to settle in Mousehole, in 1945, rather than in St Ives. There, he painted landscapes in bold colours and expressive brushstrokes, reminiscent of the French Fauvists. Indeed, he holidayed in France, and his 1948 painting of the River Loing was sold by the Redfern to the Government Art Collection, in 1949. His painting of local houses in Mousehole was acquired by the Arts Council of Northern Ireland in 1950, while a number of landscapes were purchased by the Contemporary Art Society, and duly gifted to various public museums over the course of the next decade. Still life was another subject of particular interest; for James Beechey, his depictions of oysters, crayfish and herrings "sometimes betray an unexpected undertone of disquiet". Ryan showed regularly at the Royal Academy Summer Exhibition, from where a painting of flowers was purchased for the Tate Gallery, in 1958. A few years earlier, Manchester Art Gallery had purchased his painting of Daffodils and Tulips.

Ryan's paintings won the respect of his peers, with Heron writing a number of positive reviews for The New Statesman. His work during the 1950s was included in several major survey exhibitions at the Tate, including Figures in their Setting (1953); The Seasons (1956); and The Religious Theme (1958). After returning to live in Mousehole (having lived in London during the '50s while teaching at Goldsmiths), Ryan was elected Chair of the Newlyn Society of Artists in 1962. He was part of the seminal exhibition St Ives 1939-64: Twenty-five years of painting, sculpture and pottery, held at the Tate in 1985. Once described as "the best kept secret in the art world" by Francis Bacon, Ryan is represented in a number of major UK public collections; most recently, in 2001, Penlee House Gallery & Museum purchased his 1948 painting of Myrtle Cottage. [Redfern]