Benjamin Netanyahu has appointed a hardline supporter of the war in Gaza and longtime backer of settlements in the West Bank as his ambassador to the US as Israel prepares for the incoming administration of Donald Trump.

Yechiel Leiter, an American-born rightwing publicist and former government aide who immigrated to Israel four decades ago, was announced as Israel’s next ambassador to Washington on Friday. His son, a soldier in the Israeli Defense Forces, was killed in fighting in northern Gaza last year.

Leiter is a “highly talented diplomat, an eloquent speaker, who has a deep understanding of American culture and politics”, Netanyahu said in a statement announcing the appointment. “I am convinced that Yechiel will represent the state of Israel in the best possible way, and I wish him success in his position.”

Leiter will replace the current ambassador Michael Herzog, whose term will end on 20 January.

Leiter, who was born in Scranton, Pennsylvania, has been a prominent rightwing thinker in Israel who was chief of staff to Netanyahu when he was finance minister and an aide to the late prime minister Ariel Sharon when he was a member of the Knesset.

According to Israeli media, Leiter has been affiliated with conservative policy centres including the Jerusalem Center for Public Affairs and the Kohelet Forum.

Haaretz also reported that he was previously a member of the Jewish Defense League, which was founded by the far-right Rabbi Meir Kahane and was designated a terrorist organisation by the US for a series of attacks and assassinations. It was removed from that list for inactivity due to inactivity.

Leiter is reported to live in a West Bank settlement north of Ramallah, and is affiliated with the One Israel Fund, which fundraises for settlers. His appointment was lauded by Israel Ganz, a rightwing settler leader who called Leiter a “key partner in English-language advocacy for Judea and Samaria”, the Biblical term used by Israeli settler communities in the West Bank.

Trump during his first term reversed the US position that Israeli settlements in the occupied West Bank were illegal under international law, and a number of settler leaders have said that Israel should formally annex the West Bank following Trump’s reelection to a second term.

Leiter’s son Moshe was killed in fighting in northern Gaza last year. He was Netanyahu’s guest when the prime minister visited Washington this summer during a contentious speech before a joint session of Congress.

At his son’s funeral at the Mount Herzl Military Cemetery in Jerusalem last November, Leiter addressed Joe Biden and the “rumors that you are putting pressure on Israel to hold off, to cease the offensive”.

“If those rumors are true – I hope they’re not – but if they are true, Mr President, I respectfully ask of you, here on my son’s grave, to cease and desist,” he continued. “Stand back Mr President: don’t pressure us. Let us do what we know how to do, indeed what we must do, to defeat evil. This is a war of light against darkness, of truth against lies, of civility against murderous barbarism.

“Take it from one plain-speaking Scrantonian to another – we’re going to win this one, with you or without you,” he said. “We’re going win it hands down, because we are a people of survival, and this battle is one of survival.”