He was the son of Johann Jakob von Westerholt (1727–1814), who had been born in Koblenz and had inherited the position of postmaster.
[1] In 1755, he became Hofmarschall (essentially Chamberlain) for Alexander Ferdinand, 3rd Prince of Thurn and Taxis in Regensburg before becoming President of the Court Economy.
[2] His paternal grandparents were Johann Karl Albert von Westerholt, who owned the Vilckrath estate in the Duchy of Berg through his mother.
[3] Westerholt was a Privy Councilor and statesman who served as vice president of the government during the Napoleonic Wars.
[7] He married English born Countess Winifred von Jenison-Walworth (1767–1825), a daughter of Count Francis Jenison of Walworth who moved his family to the Electoral Palatinate.