Mija Joo
Actor: Ahn Seo-hyeon
A young girl who lives with her grandfather and animal best friend Okja in the South Korean mountains.
- Action Girl: She's a sturdy, athletic country girl who does a lot of parkouring throughout the movie.
- Determinator: She is relentless in trying to find Okja and bring her back home.
- A Girl and Her X: A girl and her pet superpig, whom she has raised since she was only four. Her determination to keep Okja safe is what sets the plot into motion.
- Heartwarming Orphan: Her parents died some time before the movie began, so she lives with her grandfather.
- Raised by Grandparents: She is raised by her grandfather.
- Red Is Heroic: She wears a bright red jumper for more than half the movie.
Okja
One of the 26 superpigs that were distributed all over the world by the Mirando Corporation.
- Break the Cutie: What happens to her in the laboratory. First, she's raped by a Frankenstein's monster of a superpig who looks nothing like her or the rest of her species, and then she has pieces of flesh removed from different parts of her body so that a focus group can taste it.
- Damsel in Distress: A non-human example. The whole story revolves around Mija rescuing her from the slaughterhouse.
- Gentle Giant: She's humongous, but good-natured.
- Heroic Sacrifice: She allows herself to fall off the side of a rocky precipice to save Mija from taking the fall herself. She survives.
- Loyal Animal Companion: To Mija.
Lucy Mirando
Actor: Tilda Swinton
The powerful CEO of the Mirando Corporation looking to make profit off of Okja.
- Affably Evil: She might be the CEO of a morally corrupt company, but she is very accommodating to Mija and seems to sympathize with her situation.
- Big Bad: During the first half of the film.
- Big Bad Ensemble: With her sister, Nancy.
- Freudian Excuse: It is heavily implied that her father is the source of many of her issues.
- Lesser of Two Evils: She is definitely a Corrupt Corporate Executive and a hypocrite, but out of all her family members she's the least evil and has the highest standards.
Dr. Johnny Wilcox
Actor: Jake Gyllenhaal
A zealous zoologist and TV personality now working for Mirando.
- The Alcoholic: During the scene where he mistreats Okja in the lab, Wilcox is clearly drunk.
- Depraved Kids' Show Host: Played with: he's an animal show host, but otherwise fits the trope to a T. On camera he's a Steve Irwin-esque nice guy and a supposed friend to all animals, but outside his show he's an alcoholic, a jerkass, and has no qualms about abusing animals.
- How the Mighty Have Fallen: Hardly anyone in the company takes him seriously anymore, even though he has served as the company's face for a long time.
Nancy Mirando
Actor: Tilda Swinton
The twin sister of Lucy Mirando.
- Big Bad Ensemble: With Lucy.
- From Bad to Worse: Even her hypocritical sister doesn't shy away from calling her a psychopath, so this is to be expected when Nancy takes over.
- Pragmatic Villainy: Obviously, since she is a businesswoman, regardless of how cruel she is. Special mention goes to when she agrees to sell Okja to Mija without a hiccup, treating it as a professional business deal, despite the other party being a 14-year-old farmer girl who had been involved with the ALF and thus caused her untold trouble.
Jay
Actor: Paul Dano
The Leader of the ALF.
- Beware the Nice Ones: Jay is a Nice Guy, but he goes absolutely apeshit on K after he reveals that he lied to them by pretending that Mija gave her consent for the mission when she really said no such thing. He kicks K multiple times while he's down without remorse.
- Friend to All Living Things: In his own words, Jay "holds all creatures dear to his heart", but he can make an exception for Nancy.
- Nice Guy: Aside from his campaign to free Okja from an abusive environment run by a corrupt corporation, he also cares for Mija's well-being and tries to protect her from the harshest parts of his actions.
- Sharp-Dressed Man: Jay is only ever seen wearing suits, aside from the post-credits scene, where he has just been released from a stay in prison of unspecified length.
- Tranquil Fury: While beating the crap out of K after finding out he lied about Mija's agreement to their plan, he barely raises his voice, despite being clearly outraged.
Red
Actor: Lily Collins
A member of the ALF.
- Token Female: She is initially the only woman shown in the ALF. This is later subverted when other female members of the ALF are shown among the crowd at Mirando's presentation.
Silver
Actor: Devon Bostick
A member of the ALF.
- Straw Vegetarian: Exaggerated. Silver tries to avoid eating at all, considering all food production to be exploitative.
K
Actor: Steven Yeun
A member of the ALF.
- Bilingual Bonus: He's the only member of the ALF who can speak Korean, meaning he's the only one of them who can actually speak to Mija without a problem.
- Easily Forgiven: He is welcomed back into the ALF without a hitch after saving Jay and Mija from the police at the best superpig contest.
- Glory Seeker: He ignores Mija's request to take Okja back to the mountains so that he and the rest of the ALF can have the glory of bringing down the Mirando corporation.
Hee-bong Joo
Actor: Byun Hee-bong
Mija's grandfather.
