All of Trump's business and financial assets will be placed into the trust before he is inaugurated Jan. 20, according to a lawyer involved in the arrangement.
It was not immediately clear who will control the trust.
Trump will resign his role at the Trump Organization, his worldwide empire, and transfer control to his two adult sons and an in-house executive, the lawyer said.
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Outside ethics lawyers have repeatedly urged Trump to liquidate his holdings and hand the proceeds over to an independent trustee who controls them without his knowledge, a structure known as a blind trust.
Maintaining an ownership stake in his properties, they said, leaves the possibility that Trump's personal profit motive could influence his decisions as president.
The lawyer, who briefed reporters ahead of Trump's news conference, dismissed a blind trust as unrealistic.
The lawyer stressed that conflict-of-interest laws do not apply to the president and said the steps are simply meant to "make it clear that he would not be exploiting the office of the presidency for his personal benefit."
The lawyer said the Trump Organization will not enter new deals in foreign countries while Trump is president. Any domestic deals that could raise conflict concerns will need the written approval of a newly appointed ethics officer, the lawyer said.
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Trump officials are "in the process of interviewing stellar candidates" who are "all experts in government ethics," the lawyer said. The lawyer did not expand on how the ethics adviser will be selected to assure the person is independent and unbiased.
The Trump Organization will also add a chief compliance officer to its leadership ranks.
In the weeks since his election, the Trump Organization terminated all unfinished deals, and Ivanka Trump, who is expected to move to Washington and play a role in his presidency, will relinquish her roles at the Trump Organization, the lawyer said.