 He was elected MP for Rochester in 1621 and again in 1628 and held the seat until 1629 when King Charles I decided to rule without parliament for eleven years.He was made vice-admiral of Kent in 1627.In April 1640, Walsingham was re-elected MP for Rochester for the Short Parliament and again in November 1640 for the Long Parliament when he sat until 1653, surviving Pride's Purge.