Hogwarts School of Witchcraft and Wizardry had a staff of capable, wise, and powerful professors in charge of shaping the futures of Britain's young witches and wizards. They were never the focus of the sprawling story, but enough information was available to help readers place them into one of Hogwarts' iconic houses.
Indeed, many of these professors would've felt at home in more than one house, even if they exhibited traits that made them a better fit for one or the other. However, others matched one particular house to a tee, to the point where the Sorting Hat wouldn't hesitate in placing them.
Dolores Umbridge - Slytherin
People evolve throughout their lives, acquiring new values and beliefs. Most people evolve from their teenage selves, explaining while some Hogwarts teachers fit into a different house in adulthood. However, there are also those who never change and become even worse as adults; such is the case of Dolores Umbridge.
Umbridge embodies the worse qualities of Slytherin house. She's overly cold, completely selfish, terribly ambitious, and always prepared. Umbridge hides beneath a veneer of girliness, disguising the ugly in her with multiple shades of pink. Umbridge is one of the best female movie villains, a character who fans despise more than Voldemort himself.
Filius Flitwick - Ravenclaw
Flitwick is one of the first Hogwarts teachers that Harry meets. Although he never develops a close relationship with the Boy Who Lived, Flitwick is a staple of the series, appearing in practically every book in the Potter series. He is the Charms Master and the Head of Ravenclaw house, a role he greatly enjoys.
Like Umbridge, adult Flitwick would be in the same Hogwarts house as his teenage self. He remained committed to knowledge and continued exhibiting the traits that made him an ideal candidate for the house of the raven.
Severus Snape - Slytherin
Besides Dumbledore and Voldemort, Snape is arguably one of the best characters in the Harry Potter movies. He is the Potions Master, the head of Slytherin house, and a secondary antagonist throughout the entire series. Snape detests Harry but still acts as his guardian, protecting him from the shadows.
Snape is brave in his own way, a quality that might make him the perfect Gryffindor. However, his Slytherin qualities are more powerful. Snape is resourceful and highly adaptable, capable of fooling Voldemort into believing he was still a Death Eater. Snape was also bold and cunning, a Slytherin through and through.
Sybill Trelawney - Slytherin
Sybill Trelawney is arguably the most eccentric member of the Hogwarts staff, and that's saying something. She loves talking in an ethereal voice, delivering fatalistic omens to every student who crosses her path. Trelawney believes herself a great seer, and while most of her predictions are useless, she was behind two of the series' crucial prophecies.
A Ravenclaw during her Hogwarts years, Trelawney might be a better fit for Slytherin in her adulthood. She was self-reliant, very selfish, and with an overblown idea of herself. Trelawney had no problem manipulating the truth and making those around her believe it, gifts that her fellow Slytherins would greatly appreciate.
Gilderoy Lockhart - Slytherin
A celebrity in the Wizarding World, Gilderoy Lockhart was an institution in matters of the dark arts. He supposedly fought numerous dark creatures, authoring countless books about these encounters. Of course, it all turned out to be fake, and Lockhart ended his days in St. Mungo's after his memory spell backfired.
Lockhart was a Ravenclaw during his Hogwarts years, but he's the poster child for Slytherin as an adult. He is ambitious, cunning, ruthless, and resourceful, capable of fooling the entire Wizarding World into believing his lies. Lockhart was impressive, even if he was also ridiculous.
Rubeus Hagrid - Hufflepuff
Hagrid is one of Harry's first friends. While other teachers often act like surrogate parental figures, Hagrid is always on Harry's level, a friend more than a mentor. Hagrid was ostracized because of his half-giant status throughout most of his life, so he understands Harry better than anyone else.
Despite spending his time at Hogwarts living in Gryffindor, Hagrid is clearly a Hufflepuff. He's gentle, hardworking, absurdly caring, and loyal. He's also rather careless and acts out of instinct, qualities that are very Gryffindor; however, his Hufflepuff traits are impossible to deny. Hagrid is always there to offer helpful advice and support to his friends, making him an ideal member of the house of the badger.
Alastor "Mad-Eye" Moody - Hufflepuff
"Mad-Eye" Moody was a somewhat chaotic character. He first arrives in Harry's fourth year at Hogwarts (or everyone thinks he does!), but he turns out to be an impostor in disguise. The real Alastor Moody plays prominent roles from book five on, acting as a teacher of sorts who's always ready to give some much-needed tough-love to Harry.
Despite his intimidating and somewhat off-putting appearance, Moody is a big old softy. He cares deeply about everyone around him, acting like a father figure to the Order. Sure, he is a stern and stoic father, but a father nonetheless. Tenacious, caring, and dependable, Moody is the ideal candidate for Hufflepuff, a man whose loyalty and determination remained firm until the end.
Remus Lupin - Slytherin
Like the other Mauraders, Remus Lupin was a Gryffindor, and it's easy to see why. Lupin's condition as a werewolf alienated him from the world, so, understandably, he'd be staunchly loyal and trusting of those he considered friends.
As a member of the Order of the Phoenix, Lupin was also brave, but he was never a hot-head. Indeed, Lupin was always more cold and analytical than Harry or Sirius. He was also self-reliant due to years of living on his own and very adaptable. Many fans considered Lupin a coward, while others see him as a hero; this duality of intentions and behavior makes him a perfect Slytherin, someone who was different things at different times, never quite revealing who he was within.
Minerva McGonagall - Ravenclaw
The Head of Gryffindor house, Minerva McGonagall, is a paragon of duty and knowledge. She is deeply committed to her role as a teacher and has intimate knowledge of the ins and outs of Hogwarts. McGonagall is also Dumbledore's right hand and becomes headmistress once the Second Wizarding War is over.
McGonagall exhibits some of the traits of Gryffindor, but she has far more from Ravenclaw. She values intelligence and wisdom, is inquisitive, analytical, and introspective. McGonagall is an observer who judges actions and not intentions and is always ready with a witty comment for any situation.
Albus Dumbledore - Slytherin
The Harry Potter canon reveals that Dumbledore is a Gryffindor. However, it doesn't take much to understand that he would be a better fit for Slytherin house. Dumbledore often behaved and spoke like a villain, manipulating every event and everyone around him to pursue his ultimate goals.
Sure, those goals might've been for the greater good, but it's undeniable that Dumbledore had no issue lying, manipulating, and outright cheating to get ahead. The headmaster was cold, calculating, detached, resourceful, and selfish. Now, that's a Slytherin, to a tee.