[1] A native of the Swiss canton of Uri (he was probably born in Klingnau), Zwyer initially pursued a military career.

He participated in the Battle of White Mountain in 1620, fought at Glückstadt in 1624, at Mantua in 1630, and at Nördlingen in 1634.

In 1635 he was promoted to the rank of Major-General and made a member of the emperor's staff, where he was responsible for reforming the armies following the Swedish example.

In 1648, the Tagsatzung designated him and Johann Rudolf Wettstein, the mayor of Basel, the official negotiators of the Confederacy at the Treaty of Westphalia with the task to ensure the formal exemption of the Confederacy from the Holy Roman Empire.

In winter 1650/51, the two were also sent on a diplomatic journey to Emperor Ferdinand III in order to achieve the liberation of some goods from the German Court.