An engineer by training, the American-raised Arens was instrumental in developing Israel's military and aircraft industries and served three stints as the country's defense minister. He was a longtime stalwart in the hawkish Likud party.
In the early 1980s, Arens was the first to recognize the skills of a young Benjamin Netanyahu, who then was running an anti-terror institute and working in marketing. Arens took Netanyahu under his wing and brought him into Israeli politics.
"There was no greater patriot. Moshe Arens' great contribution to our people and our state will be remembered forever," Netanyahu said in a statement.
Addressing Arens by his nickname Misha, Netanyahu concluded: "I loved you as a son loved his father."
Arens was born in Lithuania in 1925 but grew up in the United States, where he was active in the Beitar youth movement of Likud's precursor, the Herut party of Menachem Begin. He served in the American military during World War II before immigrating to Israel in 1948.
After completing his engineering degrees at the Massachusetts Institute of Technology and the California Institute of Technology, Arens settled in Israel permanently. He worked as a professor of aeronautics at the Technion — the Israel Institute of Technology — and as an executive at Israel Aircraft Industries before going into politics. Arens was first elected to parliament in 1973.
In 1982, he was appointed Israeli ambassador to the United States and named his young protégé Netanyahu as his deputy. The position gave Netanyahu great exposure, led to his posting as ambassador to the United Nations and launched his political career.
Arens later became a columnist for the liberal Haaretz newspaper and won numerous awards in Israel and overseas.
President Reuven Rivlin remembered Arens as a pillar of the Likud's ideological wing, and "a man of honor who never flinched from the fight."
"Misha was one of the most important ministers of defense the state of Israel ever had. He was not a commander or a general, but a devoted man of learning who toiled day and night for the security of Israel and its citizens," Rivlin said.
Arens is survived by his wife Muriel, four children and numerous grandchildren.