How to Write Introverted Characters
Introverts are an elusive bunch, sometimes even to other introverts. They're especially challenging characters for writers, because their arcs are largely internal. While each character will be vastly different in their hobbies, quirks, flaws, and goals, there are a few common themes you can pull from when writing introverted characters.
BEING SOCIAL IS DRAINING
No matter what your character likes or who they are, if they're an introvert, being social will always drain their batteries. The more people and the greater length of time spent with them, the more physically, mentally, and emotionally exhausted they will be. If your character is invigorated around people rather than drained, this indicates they are an extravert, not an introvert.
This doesn't mean introverts never want to be social. We just prefer dedicating our attention to one or two people at a time, preferably in a quiet atmosphere where we can focus on conversation. Introverts also enjoy being out, but it's tiring and they will always need solo recharge time after.
PRIVACY IS KEY
Something you'll never see an introvert do is blurt details about their personal life to complete strangers. We don't like gossip, we don't invest in acquaintances' lives, and we sure as hell don't want people invested in ours until we know them well enough. An introverted character might appear cagey and mysterious simply because they're not as open as extraverted characters. Their business is their own until they decide otherwise.
This means your introverted character will have a lot of inner monologues and observations but little external dialogue with people they're not close to. Two paragraphs of thought might translate to a simple "okay" in dialogue.
RELATIONSHIPS ARE DEEP AND INTELLECTUAL
Your introvert character might be loyal to certain people on principle (family or a team, for example), but their strongest attachments will be to those they share deep, intellectual bonds with. Introverts are personality-driven and cultivate relationships based on mutual respect, vulnerability, and at least some shared interests. Hence, they prefer to keep a small number of close friends rather than a wide circle of superficial ones.
THE CHARACTER ARC
The one pet peeve I and many other introverts have with "introvert character arcs" is that they almost always lead to the introvert being more social. So, in a nutshell, the arc is the introvert becoming an extravert.
Guys, we have got to stop this narrative that being introverted is a bad thing. Introversion is not a flaw that needs to change any more than someone's sexuality is. Imagine a book about a gay guy becoming straight, where the underlying message is that he "grew out of his gayness" like it was some horrible character trait.
Your character can and should have flaws, but introversion is not one of them. Focus on other things they can overcome, like a fear, a vice, a trauma. Let them become stronger in their own quiet way.
INTROVERTED CHARACTERS THAT STAY INTROVERTS
Katniss Everdeen - The Hunger Games trilogy by Suzanne Collins
Annabeth Chase - The Heroes of Olympus by Rick Riordan
Fitzwilliam Darcy - Pride & Prejudice by Jane Austen
Jane Eyre - Jane Eyre by Charlotte Bronte
Bilbo Baggins - The Hobbit by J. R. R. Tolkien
Hermione Granger - Harry Potter by J. K. Rowling