Whittington, who was the son of a knight of Gloucestershire, opened a mercer's shop in London that supplied velvets and damasks to such notables as Henry Bolingbroke (later King Henry IV). He then entered city politics and served three terms as lord mayor of London: 1397–99, 1406–07, and 1419–20. By 1400 Whittington had acquired immense wealth and commercial prestige. He made large loans to Kings Henry IV (ruled 1399–1413) and Henry V (ruled 1413–22) and bequeathed his vast fortune to charitable and public purposes.

Popular legend makes Dick Whittington a poor orphan employed as a scullion by a rich London merchant. He ventures his only possession, a cat, as an item to be sold on one of his master's trading ships. Ill-treated by the cook, Dick then runs away, but just outside the city he hears the prophetic peal of bells that seems to say “Turn again, Whittington, lord mayor of great London” (or “Thrice lord mayor of London”). He returns to find that his cat has been sold for a great fortune to a Moorish ruler whose dominions are plagued with rats. Whittington marries his master's daughter, succeeds to the business, and subsequently becomes thrice lord mayor of London. The first recorded reference to the tale appears in 1605.