Naruhito, who turns 59 on Saturday, will ascend the Chrysanthemum Throne on May 1 after Emperor Akihito abdicates.
"I feel very solemn when I think about the future," he said at an annual pre-birthday news conference Thursday. His remarks were embargoed from publication until Saturday.
"While I continue to prepare for this role, I would like to maintain the past emperors' work. I would like to think about the people and pray for the people," he said.
His wife, Masako will also assume a new role as empress. The former diplomat has suffered from stress and has often skipped public events, and it's unclear how she will manage her new role as empress.
"Although Masako is steadily recovering, her condition still fluctuates. I would like Masako to continue to slowly widen her contribution in her role," Naruhito said, adding he hopes to support his wife just as she has supported him.
Naruhito's younger brother, Prince Akishino, and his family are also expected to play a major role. The Japanese throne is only inherited by male heirs, and Naruhito's only child is a daughter. Prince Akishino and his young son Hisahito are next in the line of succession after Naruhito.
Akihito's desire to leave the throne revived a debate about the country's 2,000-year-old monarchy, one of the world's oldest, as well as discussion about improving the status of female members of the shrinking royal population.
"This problem will relate to the imperial family of the future. I would like to refrain from giving any opinions on the system," the crown prince said.
Those who are concerned about the future of the royal family with shrinking membership want to allow women to ascend the throne and others to keep their royal status so they can keep performing public duties, but a government panel has avoided the divisive issue.
Even before the 1947 Imperial Law, reigning empresses were rare, usually serving as stand-ins for a few years until a suitable male can be installed. The last reigning empress was Gosakuramachi, who assumed the throne in 1763.
Debate over the succession law, however, is emotional. Some conservatives proposed a revival of concubines to produce imperial heirs, and others argued that allowing a woman on the throne would destroy a precious Japanese tradition.