They've also built a business empire worth as much as USD 740 million that has ties around the world, newly released financial disclosures show.
What happens when their government and private sector worlds collide?
Like other federal employees, the daughter and son-in-law of the president are required to adhere to transparency and ethics rules, and by law they cannot take any action in their government positions that affects their individual financial holdings.
New disclosures of the breadth and tangle of Kushner's financial holdings demonstrate why determining whether either White House adviser is violating the rules is no simple question.
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"The problem with conflicts is that they rarely present themselves in black and white," said Peter Henning, a law professor at Wayne State University who wrote a book about public corruption.
President Donald Trump doesn't face the same issues. The president, who broke with precedent and decided to retain a financial interest in his real estate empire, and vice president are not subject to the conflicts of interest laws that govern his employees, although the anti-bribery statute and others do apply. Trump has said he believes he can't have a conflict.
White House officials, meanwhile, may face regular dilemmas, including assessing whether they're getting too close to crossing a legal line. That's not so simple.
It might "look bad" if Kushner helps negotiate a tax reform proposal that continues to allow real estate investors such as himself to carry forward losses, Henning said.
But because so many in his industry would benefit, Henning said Kushner would probably be on the right side of the conflict laws even if there is a political price to pay.
Richard Painter, a former White House ethics counselor to President George W Bush who has been sharply critical of the Trump administration's handling of conflicts issues, argues, however, that banking regulation, taxes and trade cut too close to Kushner and Ivanka Trump's interests.
"I think there are pretty clear problems with the criminal statute if they weigh in on any of those areas," he said.