Lea Kheirallah asked to take a photo with Sharaa - who was previously known by his nom de guerre Abu Mohammed al-Jolani - when he toured the Mezzeh area of Damascus on 10 December.
Before agreeing, Sharaa gestured for her to cover her hair and she complied, raising the hood on her jumper and then standing beside him for the photo.
Many video clips and pictures of the incident were shared on social media, sparking widespread outrage among ordinary users and media commentators.
People with liberal or non-conservative views saw it as a troubling glimpse into Syria's possible future under HTS, fearing increasingly conservative policies like the requirement for all women to wear a hijab, or headscarf.
France 24's Arabic channel discussed the incident, with a headline asking if Syria was "heading towards Islamic rule".
Others were sharper in their condemnation. One Syrian journalist said: "We replaced one dictator with a reactionary dictator."
On social media, other commentators warned of "ultra-extremists" ascending to power, while others decried the "forcing of a free woman" to adopt a conservative look.