Educated at Queen's College, Cork, and Trinity College, Dublin, Dowden became professor of English literature at Trinity in 1867 and lectured at Oxford (1890–93) and Cambridge (1893–96). His Shakspere: A Critical Study of His Mind and Art (1875) was the first book in English to attempt a unified and rounded picture of Shakespeare's development as an artist, studying him in terms of successive periods. His other works on Shakespeare include the primer Shakspere (1877), which was written for a nonacademic audience, and several edited collections of sonnets. He also provided the text to accompany the illustrations in Shakespeare Scenes and Characters (1876).

Dowden is also remembered for his Life of Shelley (1886) and was among the first to appreciate Walt Whitman (Whitman, Walt), becoming his good friend.