Satterthwaite, a right-hand man of James, 1st Earl of Lonsdale, in the management of his interests in the north-west, sat in Parliament on his interest and at his convenience. He followed Lonsdale’s line, deserting Pitt on the Regency but rallying to him from 1790. Unseated at Carlisle after that election, he was returned soon afterwards for Haslemere and held the seat until Lonsdale’s death. He voted for Pitt’s triple tax assessment, 4 Jan. 1798. No speech of his is known.
Satterthwaite was not continued in the House by his patron’s heir in 1802, but he remained a mainstay of the Lowthers, expressing their wishes and managing their elections at Cockermouth.