I think we’ve all asked ourselves this question at some point: Why was Peter Pettigrew in Gryffindor House?
By all accounts he is the antithesis of a Gryffindor: a treacherous coward, without a shred of moral decency – negating the great Gryffindor qualities of bravery and chivalry.
But is it so simple?
On one hand, Slytherin is a perfect fit, especially taking Phineas Nigellus’s thoughts on the matter into account.
For instance, given the choice, we [Slytherins] will always choose to save our own necks.” – Phineas Nigellus
Not to mention Pettigrew was definitely clever, resourceful, and cunning – three salient Slytherin traits. These qualities were most obviously exhibited when Pettigrew was cornered by Sirius: In cutting off his finger to fake his own death he showed remarkable resourcefulness, in yelling at the top of his lungs that Sirius was guilty he displayed his cunning, and blasting the street apart with the wand behind his back was, among other things, clever given his position.
At the same time, Pettigrew was never particularly “ambitious” or “power-hungry” – preferring to “out of cowardice, stand in the shadow of the strongest person,” according to J.K. Rowling. So he was missing one of the most important Slytherin traits.
Pettigrew as a Gryffindor isn’t as discordant as it seems either – it does take a certain amount of nerve to cut off your own hand and a significant amount of daring and bravery to willingly hang around Voldemort 24/7.
In his last moments Pettigrew displayed the dregs of Gryffindor chivalry still alive in his soul:
Pettigrew was reaping his reward for his hesitation, his moment of pity; he was being strangled before their eyes.” – Deathly Hallows, 470
So at the age of 11, before Pettigrew knew James and Lily, before he knew what “Death Eater” meant, and before he had entertained the idea of murder, it is not a stretch to imagine Pettigrew’s latent potential for both Houses was tied.
On Pottermore, J.K. Rowling supports the same – giving Pettigrew the dubious honor of being one of only two “Hatstalls” in the last 50 years. (A Hatstall is when the Sorting Hat cannot decide on which House to sort a person into for over 5 minutes.)
But J.K. Rowling also suggests the fact that Pettigrew was sorted into the wrong House (the only time she has ever hinted at such an occurrence).
Peter Pettigrew was placed in Gryffindor after a long deliberation between that House and Slytherin. The Sorting Hat, which is infamously stubborn, still refuses to accept that its decision in the case of the latter may have been erroneous, citing the manner in which Pettigrew died as (dubious) evidence.” – J.K. Rowling
Pettigrew possessed and lacked qualities of both Slytherin and Gryffindor. I would postulate that Pettigrew became a Gryffindor in the same way that Harry did: In the end, after five and a half long minutes, he asked for it.