The Israeli cabinet approved Prime Minister Benjamin Netanyahu's move to add a hardline party to his coalition on Monday, paving the way for Avigdor Lieberman to become defence minister.
The premier's office said the addition of the Israel Beiteinu party of outspoken hawk and nationalist Lieberman was approved unanimously.
Moshe Yaalon, who had been in the post for four years, resigned earlier this month citing a lack of faith in Netanyahu and warning that "extremist and dangerous elements have taken over Israel."
Lieberman, who was in the opposition since March 2015 elections but previously served as foreign minister under Netanyahu, has said he will follow sensible policies with an aim to bringing stability to Israel and the region.
But the United States has expressed concern at the formation of the most right-wing government in Israel's history.
Without Lieberman's party - many of whose voters are immigrants from the former Soviet Union like the 57-year-old himself - Netanyahu had a government with only a razor thin majority of 61 against 59 in the 120-seat Knesset.
The Israeli parliament is expected to vote on Lieberman's appointment and the addition of his party to the government later on Monday.
The addition of the five-seat Israel Beiteinu widens the majority. One lawmaker resigned last week from the party, saying she would continue as an independent in parliament.
Netanyahu has been seeking to expand his coalition, comprised already of several parties, including the pro-settler Jewish Home party of Education Minister Naftali Bennett, who until the last minute threatened not to support Lieberman's appointment, unless his own demands were met.
Bennett mainly demanded an improvement of briefings by the military to a forum of senior ministers, known as the security cabinet, who decide on matters of war and peace.
He has charged that Netanyahu takes key decisions on his own, turning security cabinet briefings into mere formalities. The crisis was solved early Monday.