GCC Biting Other People

I’ve had my Cinnamon Green cheeked conure Límon for about 4 months now and we get along great. He’s very playful with me when we are not inside of the room with his cage. Every time someone goes to interact with him he puffs up and bites them really hard. The only time where he hasn’t bitten other people is when I bring him to someone else’s house and he gets along with everyone. He never does this to me other that when he sees my barefeet. Is there anyway where I can get my conure more social around people and used to new people or my family?

My conure is a royal stinker. He's a fun mimic and an entertaining character, but...
I have reduced biting (of me or others) to almost zero over the decades... not because I've changed the bird, but I have changed me. And a lot of that has involved giving up on a lot of my desires/expectations. After years of battle, I surrendered. I don't do stuff that gets me bitten. I don't scratch his head much, ever... tail is okay. I NEVER do stuff that makes him mad... I don't touch others when he's out; I rarely try to get him to step up onto my hand first. Hand-held perch first, then hand. In some ways, I swallow my disappointment at having such a little monster for a pet, but he is what he is. I ALWAYS wear my hair down when he's on my shoulder, so all he can bite is hair. Really, I don't involve hands much... he doesn't like them. He seems to think the real ME is my head, perched on a weird moveable tree with questionable appendages.
When you're out of your house, you're off his territory, so he's chilled, I bet.
Since the Rb is fully flighted, the ONLY way I get him into the cage is to toss a chile pepper in and he flaps in after it. So food reward is a necessity for me. Time-out doesn't exist in the Rb's kingdom.
But please... listen to and try all the good advice you'll get here. Don't surrender until you know you've done your best. Then just accept and love whatever/whoever your bird turns out to be.
My darling is kind of a worse-case scenario, but we have it all worked out between the two of us.
Very, very best of luck to you.
Good for you for reaching out!
My little jerk is a beautiful, wonderful half-wild, amazing parrot, alive and living in my home. Sometimes that just has to be miracle enough.

He is doing his job and guarding the house! My JoJo was the same. When anyone comes into the house, we caged JoJo and the visitor had to give him a treat. I had to do this for about two months to redirect his behavior!

You say you've had him 4 months but how old is he? What was his life like before you?

Birds who've spend a lot of time in their cage can become cage aggressive. Also birds who are deeply bonded with a person or two can be aggressive towards others.

My Hawk Head is deeply bonded with my wife and I and is aggressive around visitors unless she's in a new place, where I assume she becomes less sure of herself and becomes submissive.

The good news is that in the case of my bird, she is kind of growing out of the aggression. She's in her twenties and over the last two years that we've had her she's become progressively sweeter around other people and since I let her wings grow, she seems even better, flying to and landing on my kids where a year ago she would put up her crest and stalk them. It may be that it took her a while to feel comfortable in her new home.

I know nothing about GCC's but I believe good care and time fixes a lot of behavioral issues.