Percy is… a complicated character. He’s simultaneously his Mum’s favorite and the black sheep of the family. From Harry’s point of view, Percy is a pompous guy whose demeanor sometimes crosses into arrogance. He’s ambitious, and that ambition will lead him to be estranged from his family. While his mother “grieves” her prodigal son, the rest of the Weasleys react with anger and shun him. Percy will ultimately redeem himself (for real, not like Draco Malferret “redeemed” himself) by coming to the battle of Hogwarts and reconciling with his family before kicking several Death Eaters’ arses, and even Transfiguring his former boss into an urchin while delivering the mythic punchline “Hello, Minister! Did I mention I’m resigning?” (which I personally feel reaches the “There’s no need to call me sir, Professor” in terms of raw sass).
Percy provides a lot of comic relief in the first books, simply by being himself and being constantly challenged in his authority by the twins. This sort of interaction is eerily reminiscent of the way Ron and Hermione challenge each other (ie Ron cracks a joke and Hermione chastises him for not being serious, or Hermione will go in lecture mode and Ron will tell her to get to the point).
But that’s not all there is to him - sure, his dichotomy with the twins is one of the main reasons why he’s so funny in the first place - but what is incredibly endearing about Percy is that he’s got genuinely good intentions.
When Percy breaks away from his family in OoTP, Harry is bewildered. Harry tells us in his narration that he would never have expected Percy to do this. Percy, who, in all his awkwardness and pompousness, was still someone who tried to help Harry find his place into the wizarding world, was the one who gave Ron his pet (before we found out who that pet actually was), tried to set an example for his siblings…
Percy Weasley is not a ruthless, selfish shark who only thinks of himself and his best interests.
Percy Weasley is this guy:
Percy loves his siblings. And he especially loves his littlest brother the most out of them (no the fact that Percy loves Ron is not the only reason why I love Percy).
I feel like he really sees himself in Ron - like a bystander in his own family, picked on by the twins, wanting to prove himself - and so he reaches out to Ron, not to the twins or Ginny, but to Ron. He wants to protect his little brother - he goes very badly about it, the letter was just fifty shades of second-hand embarrassment all around, but the intention is there.
There’s some sort of naïvety in Percy Weasley. He’s a very Lawful Good character at his core - he genuinely believes that the government he serves in has the people’s best interests at heart. When his father tells him that he only got a promotion, not because of the good work he was doing, but instead because the government wants to use him, he refuses to believe so, because he has so much faith in the Ministry.
Most importantly, Percy’s good intentions never end up making him a Well-Intentioned Extremist - in Deathly Hallows we don’t see him while the Trio infiltrates the Ministry. We’re never clear on what he did during this year - but I don’t think he would have stood by and just watched while the government was rounding up Muggleborns. Because Percy is a Gryffindor. An awkward, dorky, glasses-wearing lion, but a lion nonetheless.
Just… look at this guy.
“First–to Mr. Ronald Weasley…for the best-played game of chess Hogwarts has seen in many years, I award Gryffindor House fifty points.” Gryffindor cheers nearly raised the bewitched ceiling; the stars overhead seemed to quiver. Percy could be heard telling the other prefects, “My brother, you know! My youngest brother! Got past McGonagall’s giant chess set!” - Philosopher’s Stone
Look at how proud he is of Ron! He’s not doing this for his own personal gain - what does it matter to others that Percy’s brother is clever? It doesn’t! He’s just so proud that his little brother is so smart, and he’s going to make sure people know. And with how little praise Ron gets throughout the series, this is genuinely a heartwarming moment.
Madam Pomfrey, the nurse, was kept busy by a sudden spate of colds among the staff and students. Her Pepperup potion worked instantly, though it left the drinker smoking at the ears for several hours afterward. Ginny Weasley, who had been looking pale, was bullied into taking some by Percy. - Chamber of Secrets
Yep, that’s Molly’s son alright
“That’s what I told Ginny,” said Percy fiercely. “but she still seems to think you’re going to be expelled, I’ve never seen her so upset, crying her eyes out, you might think of her, all the first years are thoroughly overexcited by this business -” - Chamber of Secrets
Seriously. Percy Weasley, a Slytherin? Have you ever met him? Never in a million years.
Ginny Weasley, who sat next to Colin Creevey in Charms, was distraught, but Harry felt that Fred and George were going the wrong way about cheering her up. (…) They only stopped when Percy, apoplectic with rage, told them he was going to write Mrs Weasley and tell her Ginny was having nightmares. - Chamber of Secrets
Look at him. Absolutely zero chills. He’s just telling them his master plan outright and his master plan is… to write his Mum. Percy is no Slytherin. Come on now.
Hands were raining down on their backs. Harry had a confused impression of noise and bodies pressing in on him. Then he, and the rest of the team, were hoisted onto the shoulders of the crowd. Thrust into the light, he saw Hagrid, plastered with crimson rosettes -- "Yeh beat 'em, Harry, yeh beat 'em! Wait till I tell Buckbeak!" There was Percy, jumping up and down like a maniac, all dignity forgotten. Professor McGonagall was sobbing harder even than Wood, wiping her eyes with an enormous Gryffindor flag; and there, fighting their way toward Harry, were Ron and Hermione. - Prisoner of Azkaban
Just putting this one here - because people always forget that Percy, despite not being a Quidditch player himself, is entirely capable of enjoying the sport… and dare I say, being a huge fanboy.
Percy seized Ron and was dragging him back to the bank (”Ger-off, Percy, I’m all right!”) - Goblet of Fire
Ron be nice to your big bro he was so worried
The judges went into a huddle, Madam Pomfrey had gone to rescue Ron from Percy’s clutches. - Goblet of Fire
AWWW HE JUST WON’T LET GO
… but Percy lay across Fred’s body, shielding it from further harm, and when Harry shouted “Percy, come on, we’ve got to move!” he shook his head. “Percy!” Harry saw tear tracks streaking the grime coating Ron’s face as he seized his elder brother’s shoulders and pulled, but Percy would not budge. - Deathly Hallows
Like many others, I’m in denial over that particular character death, but - look at this. Look at this, then look me in the eyes and tell me Percy didn’t care for his family. Go on. Just try.
Ron joined Bill, Fleur, and Percy, who flung an arm around Ron’s shoulders. - Deathly Hallows
Percy is just… I can’t help but love him. He’s a genuinely good person who got swallowed up in his ambition and pride but ultimately made amends. Genuinely believed he was doing good, even if it meant going against his family, and when he realized he had been mistaken, he came back to fix his mistakes. He owned up to them and decided to do better.
Percy Weasley. Remember him, the next time you try to complain about how “poor Draco didn’t get a redemption arc!! :’(”
Forget the ferret and look at Percy Weasley.
(As an interesting aside, Percy coming back to fight in the Battle of Hogwarts was not included in the Deathly Hallows movies.