In his homeland, where his idol is a champion and a congressman and the people's king, he is the heir apparent.
In his family's San Leandro home, he is ostracized.
The father says his son, upon meeting money and fame, abandoned his family.
The son implies now that he has become the champion his dad wanted him to be, there is bitterness and resentment.
"My whole family hates me," Nonito Donaire Jr. says. "They want me to lose. They pray for me to lose."
"No," Nonito Donaire Sr. says, his anguish evident. "He turned his back on us."
This is the baggage the son takes into the ring for the biggest fight of his career. It's the burden upon his slender shoulders as the 28-year-old Donaire (25-1) seeks the belts of WBC/WBO bantamweight champion Fernando Montiel.
The scheduled 12-round bout Saturday in Las Vegas will be shown live on HBO. Nonito's friends from Undisputed Gym in San Carlos, where he trains, will watch. Millions of fans, especially in the Philippines, will tune in to see the young man many hope can trace the footsteps of the legendary Manny Pacquiao.
The father, who introduced his son to the sport, will close his eyes to the event.
"I won't watch the fight," Nonito Sr. says. "Just wish him luck. That's it."
A Philippine army veteran and former amateur fighter, Nonito Sr. opened the boxing door for "Jun-Jun" and his brother, Glenn. The family was by all accounts poor in the Philippines, but when the father discovered he had American citizenship, it moved to California in 1993 and settled in San Leandro.
Trying to steer the boys from negative influences, Nonito Sr. began taking them to King's Gym in Oakland, where they showed an aptitude for boxing, becoming accomplished amateurs and turning pro, all with dad in their corner.
Glenn was rocked by Vic Darchinyan in October 2006 and eventually lost his desire for the sport. Jun-Jun avenged his brother's loss in July 2007, dropping Darchinyan with a textbook left hook that might be the prettiest punch of the decade.
It was the defining moment of Jun-Jun's career, bringing him an IBF flyweight title, making him a YouTube sensation and earning an invitation from the Philippine president.
It also initiated the most turbulent year of his career and, quite likely, his life.
Jun-Jun got engaged to Rachel Marcial, a Filipina Tae Kwon Do master and model (they married Aug. 8, 2008), replaced promoter Gary Shaw with Bob Arum's Top Rank, split with his father and, shortly thereafter, the rest of his family.
The father suggests the estrangement is directly related to the interference and manipulation of his daughter-in-law.
"They blame me, say I stole money from him," the father says, rushing his words. "He changed a lot. We are poor. Maybe that's why he doesn't care about us anymore."
Jun-Jun defends his wife, his independence and his right to seize control of his career.
"They want to see me fall on my face," he says. "That makes me better, gives me extra motivation."
Maybe it does drive him. Since his KO of Darchinyan, Jun-Jun is 7-0, only once requiring all 12 rounds. He has accumulated and relinquished two title belts, moving up in weight. Ring Magazine ranks him No. 5 in the world in the pound-for-pound listings.
Yet Jun-Jun can't escape Nonito Sr. Every son who has had such a close relationship with his father has an intrinsic desire to impress him, if not exceed his expectations. So he battles not only his opponent but a need to succeed on his own.
The son reached out last year. His father, who trains out of Kennel Boxing in San Leandro, had a fighter, Ciso Morales, on the same card in Las Vegas, so Jun-Jun invited his dad to see him fight for the first time since they split.
"They left before my fight," Jun-Jun says wistfully. "Just walked out."
Nonito Sr. says he left the arena because he was upset with and concerned about Morales, who appeared to be hurt badly in a first-round loss to Montiel.
"But I don't want him to lose," the father says of his son. "I trained him since he was 10. I sacrificed for him to become what he is: a world champion."
Though the wall between them remains tall and sturdy, they can't seem to agree on why it exists, much less when or if it might come down. They are proud and stubborn, but blood nonetheless. Someday, perhaps, they'll become family again.
Meanwhile, they are identical in one respect. Each stands his ground, waiting for the other to come forth to apologize.
Contact Monte Poole at firstname.lastname@example.org.