Born in London, Leeson developed an early interest in the theatre through the encouragement and support of her friends exacerbated by the frequent absence of her father from the family home owing to the long hours he worked in his printer's business.
The Irish actor Charles Macklin took her on as an apprentice and in 1771 she accompanied him to Ireland where she made her début at the Crow Street Theatre in Dublin.
[2] Leeson played a number of roles on her tour of Ireland with Macklin's company including Portia in The Merchant of Venice and Desdemona in Othello.
[4] The quality of her acting was debated: Joseph Haslewood claimed her occasional appearances on the London stage (103 appearances between 1775 and 1791) were largely owing to her wanting to provide for her large family rather than through a desire to display her talent.
[5] However, another critic said of her first appearance at Covent Garden that 'there was an ease and nature in her deportment and dialogue that entitles her to encouragement',[6] while Tate Wilkinson described her as 'an amiable handsome woman, and a pleasing actress'.