He would start his military service in the Swiss guards in the service of France in 1751. He did not enjoy his time in Paris and very happily returned to Bern after only 18 months. In 1757 he was made a Major in the Bernese military for Emmenthal and Aarau, and in 1760 was made a Captain in the Grenadiers.
From 1760 to 1770 he helped oversee the lands of Vaumarcus for himself and his brothers, Charles and Louis. David and his brothers had to step in and rescue the castle from their father who lived far beyond his means and would eventually have sold Vaumarcus as he did most everything else left to him by his father.
In 1764 David became a member of the Grand Council of Bern and would later serve as Governor of Sumiswald from 1770-1776. David would be the second de Büren to hold this position. David's ancestor Victor de Büren would serve at Sumiswald from 1679-1701.
Château of Sumiswald
de Büren crest that hung in the Castle of Sumiswald to commemorate David's service
In 1766 he would marry Susanne Dorothée Berseth (1741-1823) daughter of Charles Berseth, Governor of Thorberg and Salomé de Jenner.
His wife would give him one son:
1. Charles Louis (1767-1851) ∞ Madelaine Elisabeth de Steiger