 At his return to Bern in 1645, he became a member of the canton's Grand Council and seven years later, a member of the city council ("Kleiner Rat").Sigmund von Erlach commanded the Bernese troops in the Swiss peasant war of 1653, putting down the rebellion of the rural population with force.He also commanded the troops of Bern in the First war of Villmergen, a religiously motivated civil war in the Old Swiss Confederacy that the Protestant cantons lost.