“Ariana gives us another opportunity to challenge the old assumption that you have to look Japanese to be Japanese,” said Megumi Nishikura, a half Japanese, half Irish-American filmmaker who is co-director of the 2014 documentary “Hafu.”

Ms. Miyamoto said it was a personal loss that motivated her to join the Miss Universe competition last year. She said one of her friends, a half-white American who was born and raised in Japan, hanged himself because he was tired of being mocked for being unable to speak English despite having non-Japanese features.

“He said there was nowhere where he felt at home,” Ms. Miyamoto said. “I thought that if I can win, I could prove that Japanese don’t all have to look the same. I could prove that this is our home, too.”

Ms. Miyamoto said she also endured slurs growing up in the gritty southern naval port of Sasebo, where her mother’s family raised her after her father left Japan when she was an infant.

In school, she said, other children and even parents called her “kurombo,” the Japanese equivalent of the N-word. Classmates did not want to hold her hand for fear her color would rub off on them.

“I used to come home angry at my mother,” Ms. Miyamoto recalled. “I’d ask her, ‘Why did you make me so different?’ ”

She said everything changed at age 13 when she decided to reach out to her father, who invited her to his home in Jacksonville, Ark. She said she will never forget the moment she first saw her father and his relatives.