Murphy, Denis Brownell (c.1745–1842), miniature portrait painter, was born in Dublin; nothing is known of his parents. He was educated at the Dublin Society drawing schools, where he was taught by Robert West (qv) and received a prize for drawing (1763). Murphy exhibited miniatures at the Society of Artists in Ireland exhibitions in 1765 and 1768. He advertised his miniature portrait practice in Dublin newspapers and was employed by a number of jewellers to supply miniatures. In these advertisements his various addresses are recorded: George's Lane (1763–5), Great George's St. (1768). In the 1770s he went to London, where he was attached to Queen Charlotte's household. He returned to Dublin in 1792, where he is recorded with an address at Dame St. (1792) in the employment of the jewellers Bates and Bird. Later he advertised from 92 Grafton St. (1793) and College Green (1794–8).
Murphy was a patriot and strong sympathiser with the United Irishmen. He took part in the rebellion of 1798. Afterwards he moved to the north of England, where he settled at Whitehaven, Cumberland. In 1802 he moved with his family to Newcastle-upon-Tyne. At this time he is known to have worked at Lancaster and in Scotland. The Murphy family settled at Hanwell, Middlesex, in 1803, and in Pall Mall, London, in 1806.
Denis Brownell Murphy was a highly successful and prolific miniaturist. He painted a number of distinguished artists such as the illustrator and engraver Thomas Bewick (1753–1828) (Hancock Museum, Newcastle-upon-Tyne), and did a drawing of the landscape painter John Crome (1768–1821) (National Portrait Gallery, London) and a miniature of William Wordsworth (NGI). The Wordsworth portrait is of particular importance as it is mentioned in Wordsworth's own correspondence and shows the poet as a young man at the beginning of his acquaintance with Coleridge. Murphy's portrait of Sarah, countess of Warwick, in Elizabethan dress (private collection) was exhibited in an exhibition of Irish miniatures at Rothe House, Kilkenny, and the Hunt Museum, Limerick, in 1999. Although the quality of some of his work varied greatly, he was a competent painter in watercolour on ivory. He was particularly adept at painting miniature versions of oil portraits. These were relatively large, painted on rectangular pieces of ivory about 10 cm (4 in.) high. By 1810 he was appointed painter-in-ordinary to Princess Charlotte and received many commissions to paint members of the royal family. He painted portraits of Princess Charlotte (Dutch Royal Collection and British Royal Collection at Buckingham Palace). Murphy painted miniature versions of some of Lely's famous ‘Beauties’ then at Windsor Castle (later at Hampton Court) and was commissioned by Princess Charlotte to paint a series of miniature copies of these and some other royal portraits. Murphy was given an apartment at Windsor and was visited by members of the royal family. The set of miniatures was incomplete at the time of Charlotte's death in 1817. The finished series and a request for payment were submitted, but to the painter's great disappointment the series was returned. The set of twenty-one miniatures was purchased by Sir Gerard Noel (sold at Christie's 1949). The miniatures were engraved and published with text supplied by Murphy's daughter, the writer and art historian Mrs Anna Brownell Jameson (qv) (1794–1860). The work was published as The beauties of the court of King Charles the Second in 1833.
Murphy exhibited a portrait at the British Institution and is recorded as exhibiting miniatures in enamel and on ivory at the Royal Academy from 1800 to 1827. He died in London in March 1842 and was survived by his wife and five daughters; no other details of the marriage are known.