Monday's 7-0 decision upheld two lower court rulings in the case of Ronald and Erika MacKinnon, who separated in 2002 after 11 years of marriage. Their daughter, Justine, is 7.
Hours later, Chief Justice James R. Zazzali put the ruling on hold so the court could consider whether to give the father time to appeal to the U.S. Supreme Court.
Ronald MacKinnon noted Japan is not among 79 nations that have signed the Hague Convention, which seeks to return abducted children, meaning he would have no legal recourse.
The Supreme Court found that Erika MacKinnon had obeyed all court orders.
"We reiterate that 'fear alone is insufficient to deprive' a custodial parent of the ability to relocate with a child if the parent has a good faith reason for the move and has shown that the child will not suffer from it," Zazzali wrote for the court.
Zazzali noted that lower courts had agreed the child's best interests would be served by moving to Japan with her mother, who is a Japanese citizen and has relatives there, according to court papers.
Ronald MacKinnon's attorney, Michele D'Onofrio, said they would consider appealing to the U.S. Supreme Court. The girl's father is a construction worker sidelined with an injury, she said.
She said that while Erika MacKinnon, a massage therapist and housekeeper, has not blocked visitation in the past, she would probably not earn enough on Okinawa to bring their daughter back with any regularity.
"The likelihood of frequent travel, three times a year as ordered by the trial court, is unlikely," D'Onofrio said.
D'Onofrio said she hoped the U.S. high court would accept the case to resolve conflicting decisions by state courts in similar cases.
Erika MacKinnon's attorney, Christina Reger, said they would ask the state Supreme Court to put its ruling into effect and let MacKinnon and her daughter move.
"There's not a federal issue here, so we don't anticipate the Supreme Court taking this," Reger said.