Walker, William (1791–1867), engraver, was born on 1 August 1791 at Markton, Musselburgh, Midlothian, the son of Alexander Walker and his wife, Margaret Somerville, of Lauder. His father manufactured salt from sea water until this business became unprofitable. The family then moved to Edinburgh, where Walker was apprenticed to the engraver E. Mitchell. In 1815 Walker moved to London and studied line engraving with James Stewart, stipple engraving with Thomas Woolnoth, and mezzotinting with Thomas Lupton. In 1819 he returned to Scotland and was employed to make the engraving of Sir Henry Raeburn's equestrian portrait of the fourth earl of Hopetoun (1821) and a number of portraits, notably those of Sir Walter Scott and Raeburn himself (both 1826) and Lord Brougham (1828).

Walker's body of work included 107 plates (twenty-three stipple, eighty-one mezzotint, and three in mixed method), of which 100 are portraits of contemporary figures which he published himself. He also produced historical group pictures, most notable being 'The Reform Bill Receiving the Royal Assent' (1832), 'The Reformers Presenting their Protest at the Diet of Spires', (1844, larger version 1845), 'The Aberdeen Cabinet Deciding Upon the Expedition to the Crimea', (1857) and 'The Distinguished Men of Science', engraved with assistance from G. Zobel, after a drawing by John Gilbert, J. L. Skill, and Walker himself (1862). This last work includes fifty-one portraits and occupied Walker for six years. Late in life Walker set up a commercial portrait photography business. Examples of his prints are in the British Museum, the Victoria and Albert Museum, and the National Portrait Gallery, London.

In 1829 Walker married Elizabeth Reynolds, the daughter of the engraver Samuel William Reynolds, and settled in London at 64 Margaret Street, where he lived for the rest of his life. They had six children: William, Samuel Alexander, Elizabeth, Marion, Kate, and Jane. William Walker died at his house in Margaret Street on 7 September 1867 and was buried in Brompton cemetery.