Evelyn began lessons with a drawing master at the age of 15, followed by prize-winning studies at South Kensington and Slade Schools; in 1875 she paid her first visit to Italy. Her exhibition debut in 1876 at the Dudley Gallery with "St Catherine of Alexandria" was followed by an invitation to show at the Grosvenor Gallery, where she exhibited regularly. In 1887 she married William de Morgan, ceramicist and associate of William Morris, with whom she shared a deep interest in spiritualism.
From 1888 to 1901, she became a regular exhibitor at the New Gallery, establishing a reputation as an artist influenced by Burne-Jones. Her preferred subjects included sacred and allegorical figures and scenes, and legends with a moral or social message, treated in a fashion that exploited her superior drawing skills and design sense, with striking color and billowing draperies, often on a very large scale.
From 1890-1914, for the sake of William’s health, the couple divided their time between Chelsea and Florence; together they devised a painting method utilising glycerine which, though too troublesome to pursue, produced the clear, bright tones they sought. In 1916, her horror of the war led her to mount an exhibition of 13 works for the benefit of the Red Cross.
De Morgan died in London in 1919, two years after her husband. Her brother and sister made arrangements for her works to be shown permanently, first at Leighton House and then Old Battersea House; now owned by the De Morgan Foundation, they form one of the largest existing permanent collections of work by a single artist in Britain.