Kean was born in Dublin; he entered the Dublin Society's drawing schools in 1771 and studied ornament, landscape and figure drawing.
In 1779 he gained a silver medal of the Dublin Society for drawings of sculpture.
[1] Intending to become a sculptor, he was apprenticed to the sculptor Edward Smyth, but he established himself as a miniature portrait painter, moving to London where he practiced successfully.
Kean, a hot-tempered man, quarrelled with his wife and stepchildren over the business, and lawsuits resulted.
In 1811 Kean disposed of the factory and Robert Bloor, his clerk, took over.