I do a lot of unconventional sortings, but today’s will shock no one. Yes, the Grinch is a Slytherin.
“Those cunning folk use any means to achieve their ends” – this is the Grinch in a nutshell. He isn’t necessarily ambitious in the traditional sense – he doesn’t want fame, wealth, or power – but if you think of ambition as going after what you want and doing anything to achieve it, that certainly applies. He wants Christmas gone, so he dresses up as Santa Claus to literally steal it. The story even shows him as cunning: “But you know that old Grinch was so smart and so slick / he thought up a lie, and he thought it up quick”. He’s easily able to think on his feet and trick little Cindy Lou into believing he’s trying to help.
But what about the ending? Would a Slytherin really have a sudden change of heart and bring everything back? Within the Harry Potter series itself, there are plenty of Slytherins who would and do rethink their choices and undo the very thing they’ve been working towards. The Grinch is more of a Snape or a Regulus Black than a Voldemort, but he’s still definitely a Slytherin.