The protagonist of The Pearl, Kino, is a traditional hard-working man who takes great pride in his dignity and unwillingness to give in. He has tremendous love for his wife and child, which strongly motivates him to continue his grueling work. After finding the titular pearl, his ambitions skyrocket, and he becomes obsessed with the idea of freedom from oppression.

Juana, Kino's wife, holds a significant faith in religion. She prays for good fortune, and once Kino discovers the pearl, she begins to believe that the pear holds evil powers. She is a headstrong individual, though she often compromises her own beliefs or ideas in favor of Kino's.

Coyotito is an infant and consequently has few noteworthy traits. Instead, he serves as a plot device; when he is stung by a scorpion, Kino becomes obsessed with the idea of acquiring enough money to send him to the proper doctor, and the plot is thus set in motion.

Juan Thomas is Kino's brother who remains an influential and supporting figure for Kino. A man with strong family values, he becomes concerned when Kino finds the pearl. He hopes for the best for Kino and his own family.

The doctor Kino asks to help Coyotito is a European colonial who feels dissatisfied with his current lifestyle. An arrogant man who thinks he deserves better than he has, he shows his greed when agreeing to help the infant only after learning about the pearl.