Friedman, who has no diplomatic experience, is a supporter of Israel's Jewish-only settlements - which are considered illegal under worldwide law - in the occupied West Bank, including East Al-Quds (East Jerusalem).
Like some of his predecessors, Trump has vowed to move the American embassy to Jerusalem, a politically charged act that would anger Palestinians who want east Jerusalem as part of their sovereign territory.
Earlier this month, outgoing US President Barack Obama renewed a presidential waiver ordering the US Embassy in Israel to remain in Tel Aviv and not be moved to Jerusalem, despite pressure by Congress and Israel to do so.
Friedman, 57, an Orthodox Jew and a Hebrew speaker, has been an outspoken and active supporter of the settlement movement, and has argued that Israel doesn't face a "demographic threat" to its Jewish character if it fails to separate from the Palestinians.
Friedman has close ties to Jewish settlements in the occupied West Bank, which much of the worldwide community consider illegal and have proven to be a roadblock in the peace process.
"This is about as sharp a break with past policy as I've seen in the last 25 years", said Aaron David Miller, a Mideast adviser under five American presidents of both parties. Similar promises had been made by previous presidential candidates including Bill Clinton and George W. Bush. And it would isolate the USA from nearly the entire worldwide community, including its closest European allies and the Arab states it relies on to fight the Islamic State group and other threats.
"Every government, every US administration has looked at that question, has determined that the embassy is where it should be", Shapiro said. Going through with the move, he added, "will feed every jihadi's wildest dreams" because it will feed into the notion of a Jewish takeover of the city. However, Trump advisers have insisted in recent days that the president-elect will follow through on moving the embassy.
In a Trump transition team statement Thursday announcing his appointment, Friedman said he wanted to work for peace and looked forward to "doing this from the United States embassy in Israel's eternal capital, Jerusalem". Friedman this week briefed the Conference of Presidents of Major American Jewish Organizations on what to expect from a Trump presidency.
Friedman is also a fervent opponent to another orthodoxy of U.S. foreign policy, the "two-state solution" to the Israeli-Palestinian conflict, in which the territory would be shared. It is one of the thorniest issues in the Israeli-Palestinan dispute.
While Israelis are "overwhelmingly well-intentioned, well-informed, and non-hateful", the Palestinians "teach their children to hate and murder Jews", he said. Israel disputes this. There are now 400,000 settlers in the West Bank in 300 communities. The Palestinians seek east Jerusalem, home to key Jewish, Muslim and Christian holy sites, as the capital of their future state.
Trump appears serious about his intentions.
- With files from The Associated Press.
An embassy in Jerusalem would put America's Arab allies in a hard position. "His position reflects the desire to strengthen the status of Jerusalem as the capital of Israel and he understands the settlements were never the real problem area", she wrote on Facebook. One Saudi prince even has suggested the entire Islamic world would pull its ambassadors from Washington, although that is unlikely.
One option Trump allies have discussed would involve Friedman, if confirmed by the Senate, working out of an existing United States consulate in Al-Quds.
Moving the embassy isn't impossible, he said, if Trump lays the groundwork with Middle East partners. Compensation would be offered to Palestinian land owners. "The message to Abbas is that you have a burden that you have to carry to be taken seriously as a potential nation state", Friedman said. "They don't make the policy".