* Global recognition: Emma Watson (Hermione Granger) is widely recognized for her portrayal and has had significant success beyond the franchise.
* Critical acclaim: Maggie Smith (Professor McGonagall) received critical acclaim for her nuanced and memorable performance.
* Fanbase: Daniel Radcliffe (Harry Potter) has a massive and dedicated fanbase who adore him as the titular character.
* Social media presence: Emma Watson and Rupert Grint (Ron Weasley) have strong followings on social media.
Ultimately, "most popular" is a matter of opinion and perspective. All the main actresses in the Harry Potter franchise have achieved considerable success and contributed to the franchise's global popularity.