Born at Geneva, of an English father and a French mother, and brought up in France and Italy. He studied in 1882 at Lambeth School of Art, where he met Charles Shannon, with whom he soon took lodgings together, and with him founded a magazine The Dial 1889-97, and the Vale Press 1896-1904. Ricketts and Shannon were lifelong partners.

Ricketts and Shannon moved to The Vale, Chelsea. Ricketts began drawing for magazines. He regarded these drawings as mere hack work and later tried to buy back and destroy as many as possible.

Oscar Wilde delighted in the company of the young artists, calling The Vale "the one house in London where you will never be bored." Ricketts and Shannon's circle also included writers Edith Cooper and Katherine Bradley (who wrote together as Michael Field), W.B. Yeats, John Gray, George Bernard Shaw, Thomas Sturge Moore, and Cecil Lewis.

Ricketts gave up printing after 1904 and turned to painting and occasional sculpture and in 1906 began to design for the theatre, his designs including sets for Bernard Shaw's Saint Joan 1924. Ricketts exhibited at the International Society from 1906 and the Grosvenor Gallery from 1921. He was art adviser to the National Gallery of Canada 1924-31.

He remained aloof from the artistic movements of his era, and intensely disliked Post-Impressionism, but demonstrated knowledge and appreciation of the Old Masters, from earliest Greek to the Twentieth Century (especially the Italian Renaissance). Ricketts was an enthusiastic talker, intense and joyful in his approach to his life and his art. His friends found him noble and generous.

Author of The Prado and its Masterpieces (1903), Titian (1910), Pages on Art (1913), and the posthumous Self-Portrait (1939). Ricketts died in London of heart failure. A large part of the collection of works of art which he formed in association with Shannon is now in the Fitzwilliam Museum, Cambridge.