Jared Kushner will serve as a senior adviser in father-in-law Donald Trump's White House, the Trump Presidential Transition Team said Monday.

The announcement ends speculation about Kushner’s post-campaign future but fuels questions about his new West Wing role and further involvement in his family’s Manhattan real estate business.

Kushner's lawyer has said his client would step down as chief executive of the family business if he takes a White House position and divests some of his assets to comply with federal ethics laws that apply to government employees.

The law requires Kushner, who was among Trump's most trusted and powerful campaign advisers, to take more significant steps than Trump to disentangle his business interests, given that conflict-of-interest laws largely do not apply to the president.

But attorney Caleb Burns, a partner in the Washington, D.C., firm Wiley Rein, hit back Monday at Democrats like Massachusetts Sen. Elizabeth Warren and others who have suggested that Trump, Secretary of State nominee Rex Tillerson and now Kushner aren’t doing enough to separate themselves from business interests.

“Jared Kushner has done everything he’s required to do and more. He’s simply required to recuse himself from any decision that would have a ‘direct and predictable’ impact on his financial holdings,” Burns, who specializes in government ethics law, said Monday. “They're cloaking political issues in legal garb."

The transition team said Kushner will work closely with White House Chief of Staff Reince Priebus and chief strategist Stephen K. Bannon to execute President-elect Trump’s agenda.

“Jared has been a tremendous asset and trusted adviser throughout the campaign and transition, and I am proud to have him in a key leadership role in my administration” said Trump, in the announcement.

Kushner’s decision also end speculation about whether he would join Trump’s administration or take an outside advisory role.

But it will likely further ignite the political squabble over whether the 35-year-old Kushner's post violates a no-nepotism law that bars officials from appointing relatives to government positions. (Some Trump aides have argued that the law does not apply to the White House.)

Kushner, married to Trump’s daughter Ivanka, was deeply involved in the campaign's digital efforts and was usually at Trump's side during the election's closing weeks.

He has since continued to play a central role in the transition, taking part in Cabinet interviews and often getting a last word alone with Trump after a meeting concludes.

Whether Kushner, a Harvard graduate, will be an adviser on domestic or foreign policy, or both, remains unclear.

Trump has suggested since winning the White House race in November that he would like Kushner involved in helping with Middle East peace.

Kushner has never publicly distanced himself from Trump's more provocative stances, including his campaign call for a temporary ban on Muslim immigration.

The announcement follows Kushner being among the few advisers to join Trump in meeting President Obama at the White House and reports about him and his family already having decided on a home in Washington’s Kalorama neighborhood.

Like his father-in-law, Kushner pushed a mid-sized real estate company into the high-stakes battlefield of Manhattan. Though he is often viewed as more moderate than Trump, people close to him say he fully bought in to the Trump campaign's fiery populist message that resonated with white working class voters.

Prior to the campaign, Kushner and Ivanka Trump were not overtly political. Kushner's father was a Democratic fundraiser while Ivanka, whose personal brand has a focus on young working mothers, counted Chelsea Clinton among her friends.

“It is an honor to serve our country,” Kushner said. “I am energized by the shared passion of the president-elect and the American people and I am humbled by the opportunity to join this very talented team.”

FoxNews.com's Joseph Weber and Fox News' John Roberts and The Associated Press contributed to this report.