He was born at Edinburgh in 1800. His father was Thomas Bonnar a house-painter and interior designer of considerable skill, and the son, having from his early years evinced a remarkable aptitude for drawing, was apprenticed to one of the leading decorators of the time.
When George IV visited Edinburgh in 1822, Bonnar assisted David Roberts in decorating the assembly rooms for the grand state ball which was given in honour of the occasion. Shortly afterwards some signboards painted by him attracted the notice of Captain Basil Hall, who sought out and encouraged the young artist. In the year 1824 his picture of "The Tinkers " established him as a favourite with the public, and shortly after the formation of the Royal Scottish Academy (in 1830) he was elected one of the members.
In 1833 his address is given as Robb"s Court (off the Canongate).
Bonnar died at Edinburgh in 1853 and is buried in Street Cuthberts kirkyard in Edinburgh. His monument is almost identical in execution to that of his father in Dean Cemetery who had died only a few years earlier, and is therefore presumed to be by David Watson Stevenson.
William"s sister, Elizabeth Bonnar (1808-1889) married George Meikle Kemp. If true, William would be an odd choice, as one of the few non-architects in the family.
