The son of William Lewis, a linendraper on
Tower Hill, London, later an actor and manager in Ireland, he was born at
Ormskirk,
Lancashire, in or about 1748 (there is disagreement about his birth date); he had a Welsh clerical background, and was rumoured to be a great-grandson of
Erasmus Lewis. He was brought up in
Armagh. A juvenile actor from very young, Lewis first appeared as "Mr. Lewis" in the playbill when he acted Colonel Briton in
Susannah Centlivre's comedy
The Wonder. Under Willian Dawson, Lewis appeared (1770–71) at the
Capel Street Theatre in
Dublin. He rapidly became popular in the city. On 19 February 1771 he was Belcour in
The West Indian by
Richard Cumberland, a part he made his own. On 4 May 1772, at the
Crow Street Theatre.
Tate Wilkinson saw him play Romeo to the Juliet of Mrs. Sparks. ==On the London stage==