Princess Aiko, the only child of Japan's Emperor Naruhito, will begin work at the Japanese Red Cross Society in April after graduating from university.
While details of her new role are unclear, she will continue official duties with the imperial family.
The 22-year-old princess is not in line of succession as Japanese law allows only men to ascend to the throne.
Japan has the oldest continuing hereditary monarchy in the world.
In a statement, Princess Aiko said that she has "always had an interest" in the Red Cross, while her new employer added that it wants "to thoroughly make preparations so that the princess can work at ease".
The organisation has close ties with the imperial family, with previous empresses serving as honorary presidents.
In October, Princess Aiko visited the society with her parents to observe an exhibition on its relief activities following the 1923 Tokyo earthquake. In recent years, she has also expressed her sympathies to victims and survivors of natural disasters in Japan.
She is currently in her final year of study at Gakushuin University's Faculty of Letters, majoring in Japanese language and literature. The princess is generally well regarded by the Japanese public, many of whom have welcomed her new role.
'Career woman' mother
Princess Aiko's mother, Empress Masako, is known as a "career woman" princess and empress in Japan.
Educated at Harvard and Oxford, the empress is a former diplomat fluent in several languages.
In 1993, she became only the second commoner, after former Empress Michiko, to marry the first in line to the Japanese throne.
But once married, speculation raged over if and when she would produce a male heir.
The birth of Princess Aiko in 2001 was much celebrated but did not resolve the succession issue.
The Japanese government then began debating whether to change the law to allow women to ascend to the throne.
Five years later, Emperor Naruhito's younger brother welcomed a baby boy, Prince Hisahito, to avert the succession crisis.
But the pressure on then Crown Princess Masako was evident as she disappeared from public view for more than a decade.
In 2004, then Crown Prince Naruhito told journalists in unusually strong comments that his wife had "completely exhausted herself" trying to adapt to palace life.
The palace then announced that the princess was suffering from an "adjustment disorder", widely assumed to be a reference to depression.
Tabloid coverage
In recent years, the family of Prince Hisahito, who is second in line to the throne after his father, has attracted much coverage by Japanese tabloids.
His older sister, former princess Mako, married a commoner, Kei Komuro, and moved to the US after leaving the imperial family.
An alleged money dispute between Mr Komuro's mother and her former fiancé, who claimed mother and son had failed to repay a debt to him, almost threatened their marriage as public perception of the couple soured.
Mr Komuro's New York state bar exam results were treated as breaking news in Japan until he passed on his third try in 2022.
The tabloid spotlight on the Akishino family has meant that local media often makes comparisons between the princesses.
When Princess Aiko was asked about her cousin Mako's marriage in 2022, she said: "For me, marriage still seems far in the future and I haven't really thought of it. I have no particular thought of my ideal partner, but (the ability to) make each other smile seems perfect."
