Edgcumbe was returned for Fowey on his family interest. Like the rest of his family he was an Administration supporter, but he seems rarely to have attended the House, being absent at sea for long periods; he served in the Mediterranean under Byng, with Boscawen at the capture of Louisburg in 1758, and with the Channel fleet under Hawke in 1759. There is no record of his having spoken in the House.
He died 4 Feb. 1795.