 From 5 July to 14 November 1746, he was Chief Secretary for Ireland under Lord Chesterfield, then Lord Lieutenant.At the election of 1754, he was returned for Callington on his wife's interest, and was identified as a Tory.By the 1761 election, the two were separated, and Margaret put up one of her agents, Richard Stevens, in Shirley's place; he did not again sit in Parliament.