Among them, Maggie Smith, who portrayed the stern yet caring Professor McGonagall, first graced the screen in “Harry Potter and the Sorcerer’s Stone” in 2001. Her commanding performance earned her a cherished place in the franchise and a lasting legacy. Alan Rickman, known for his complex role as Severus Snape, brought depth and nuance to a character whose true loyalties were revealed as the story unfolded. Rickman’s portrayal remains one of his most celebrated roles until his death in 2016.