John Stewart was a soldier and member of the first Parliament of Great Britain, serving from 1707 to 1708. He was later Member of Parliament

Member of Parliament

A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...

 for Wigtownshire

Wigtownshire (UK Parliament constituency)

Wigtownshire, was a constituency of the House of Commons of the Parliament of Great Britain from 1708 to 1801 and of the Parliament of the United Kingdom from 1801 to 1918. It was represented by one Member of Parliament....

 from 1708–1710 and again from 1711 to 1727.

In 1710, he voted for the impeachment of Sacheverell. The same year he was promoted Brigadier-General and later served in the Peninsula commanding British forces during the War of the Spanish Succession

War of the Spanish Succession

The War of the Spanish Succession was fought among several European powers, including a divided Spain, over the possible unification of the Kingdoms of Spain and France under one Bourbon monarch. As France and Spain were among the most powerful states of Europe, such a unification would have...

.

Richard Dongworth, chaplain to the Duchess of Buccleuch, said of Stewart that he was a Court Tory

Tory

Toryism is a traditionalist and conservative political philosophy which grew out of the Cavalier faction in the Wars of the Three Kingdoms. It is a prominent ideology in the politics of the United Kingdom, but also features in parts of The Commonwealth, particularly in Canada...

who would be "episcopal or Presbyterian upon occasion".