In the knighthood letter, signed by Queen Christina, the family name was written in two different ways — first "Gyllenhahl" and then "Gyllenhaal".

On the copperplate with his coat of arms now hanging in the House of Nobility (Riddarhuset) in Stockholm, it is spelled "Gyllenhahl".

[note 1] Actor Jake Gyllenhaal, great-great grandson of the below-mentioned Anders Leonard Gyllenhaal, quipped during an interview before the British premiere of Prince of Persia that his last name was pronounced "Yil-en-hoo-luh-hay", parodying Americans' difficulties with Swedish pronunciation.

All the members of the family in the United States are descended from Hans Gyllenhaal through his great great-great grandson Anders Leonard (1842–1905) and his wife Amanda (née Nelson, 1859–1948).

In 1807, he was created a Knight of the Royal Order of Vasa for his scientific work as an entomologist, including his monograph on Swedish insects, Insecta Suecia descripta.