[2] Alexander Ferdinand was the eldest child and only son of Anselm Franz, 2nd Prince of Thurn and Taxis and his wife Maria Ludovika Anna Franziska, Princess of Lobkowicz (1683-1750).

[citation needed] From 1 February 1743 to 1745, Alexander Ferdinand served as Principal Commissioner for Charles VII, Holy Roman Emperor at the Perpetual Imperial Diet in Frankfurt am Main.

When the Diet relocated to Regensburg under Francis I, Holy Roman Emperor, Alexander Ferdinand was reinstated as Principal Commissioner in 1748.

It was for this reason that Alexander Ferdinand moved the principal residence of the Princely House of Thurn and Taxis from Frankfurt am Main to Regensburg.

Alexander Ferdinand and Sophie Christine had five children: Alexander Ferdinand married secondly Princess Louise de Lorraine (1722-1747), third eldest daughter of Louis, Prince of Lambesc and his wife Jeanne Henriette de Durfort (1691-1750), on 22 March 1745 in Paris, but she died January 6, 1747, without issue.