Maria Theresa managed to obtain considerable influence at the Austrian court when Empress Elisabeth effectively withdrew from the social scene in Vienna after the suicide of her only son, Crown Prince Rudolf, in January 1889.

Maria Theresa stood in for the Empress and carried out honours at the Hofburg Imperial Palace with the Emperor until the death of her husband in 1896 when court etiquette ruled she had to go into retirement.

[3] She remained such an influential figure behind the scenes at court after the death of her husband that when rumors spread that she was to marry the master of her household, Count Ladislaus Cavriani (1851–1919), no one dared to say a word against her.

After his departure from Austria (he never formally abdicated), Maria Theresa accompanied Karl and his wife Zita into exile in Madeira, but eventually returned to Vienna, where she spent the rest of her life.

In 1929, following a decline in her finances, Maria Theresa engaged two agents to sell the Napoleon Diamond Necklace, a piece inherited from her husband, in the United States.