She was a member of the House of Welf and was princess-abbess of the Imperial Free secular Abbey in Gandersheim.

Therese Natalie was the sixth daughter of Duke Ferdinand Albert II of Brunswick-Bevern (1680-1735) and his wife Antoinette Amalie (1696-1762), a daughter of Duke Louis Rudolph of Brunswick-Wolfenbüttel and Princess Christine Louise of Oettingen-Oettingen.

Therese Natalie was a first cousin of Archduchess Maria Theresa of Austria, Queen of Hungary and Bohemia.

Efforts to marry Princess Therese Natalie with an Archduke of Austria or a French prince failed because she was unwilling to convert to the Catholic faith.

During her period in office, Therese Natalie often stayed at the court of her elder brother Charles I in Brunswick.