But she will not have an official title or salary when she works in the West Wing - the hub of US executive power.
The official also confirmed media reports that the 35-year-old would have access to classified information.
Her role will be to serve as Donald Trump's "eyes and ears" while providing broad-ranging advice, her attorney was quoted as saying by Politico.
Ivanka, who has her own fashion brand, will be joining her husband Jared Kushner, who is a senior adviser to the president.