At the 1690 English general election, Erle was returned as MP for Wareham in a contest. In July 1690, he took part in the Battle of the Boyne and the Siege of Limerick. He also took part in the concluding Battle of Aughrim in July 1691. Erle was infrequently in Parliament and his contributions were usually on military matters. In 1692, he was posted to Flanders and on 3 August 1692 was Colonel of the former Luttrell's Regiment at the Battle of Steenkerque. Henceforth, the regiment Erle raised in 1689 became the 2nd Battalion of the former Luttrell's Regiment, later the Green Howards. In Parliament he spoke against a motion to employ only English officers in the army and became involved in mutiny bills. In 1693, Erle was promoted to Brigadier-General, and was wounded in the Battle of Landen on 22 March 1693.