Israeli Defense Minister Moshe Arens, right, with Prime Minister Yitzhak Shamir in 1984. Mr. Arens was both a rightist and a liberal idealist, a champion of equal rights for Palestinians who also advocated for the annexation of the West Bank. (Jim Hollander/EPA-EFE)

Moshe Arens, an aeronautical engineer turned Israeli statesman who served three times as defense minister, sought to forge closer ties with the United States and became a mentor, patron and sometime critic of Prime Minister Benjamin Netanyahu, died Jan. 7 at his home in Savyon, near Tel Aviv. He was 93.

Mr. Arens died in his sleep, according to Israeli news reports, which did not give a precise cause. “There was no greater patriot than him,” Netanyahu said in a statement.

Cool and professorial, with an analytical bent and gentlemanly demeanor, Mr. Arens was one of the last survivors of his country’s founding generation. A former member of the Irgun, the paramilitary group that fought for Israeli independence under British rule, he was both a rightist and a liberal idealist, a champion of equal rights for Arab Israelis who also advocated for the annexation of “Judea and Samaria,” his preferred term for the Palestinian territories in the West Bank.

But Mr. Arens, who had studied at MIT and Caltech, become a favorite of Republican legislators and worked closely with members of the Ronald Reagan administration, appearing frequently on American news programs to argue on behalf of Israel’s invasion of Lebanon in the summer of 1982.

When Defense Minister Ariel Sharon was forced to resign one year later, in the aftermath of the Sabra and Shatila massacre in Beirut, Mr. Arens took his place. He went on to oversee sweeping reforms that established a new command structure and missile system, leading to the beginning of Israel’s withdrawal from Lebanon.

After his initial one-year stint as defense minister — considered the country’s second-highest office — Mr. Arens held the position again in the early 1990s, when he unsuccessfully called for a ground operation to knock out Iraqi Scud missiles during the Persian Gulf War, and served as defense minister for a third time in 1999.

Mr. Arens in 1989. He served three times as defense minister and was a leader of the conservative Likud party. (Jim Hollander/EPA-EFE/Shutterstock)

“Misha was one of the most important ministers of defense the state of Israel ever had,” President Reuven Rivlin said in a tribute. “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.”

Indeed, Mr. Arens insisted he was more interested in designing jet planes than in navigating the turbulence of Israeli politics. Before launching his political career in the 1970s, he played a key role in the development of Israel’s aerospace industry, teaching some of the country’s first aeronautical engineering students as a professor at the Technion, a leading research university in Haifa.

He also served as vice president for engineering at Israel Aircraft Industries, where he shepherded the development of new missile systems and laid the groundwork for the Lavie, a high-tech jet fighter that was developed using $1.5 billion of U.S. aid money — funding that Mr. Arens was widely credited with obtaining.

When the aircraft was abandoned in 1987, amid pressure from the U.S. government and concerns over its mounting cost, Mr. Arens responded by resigning from his cabinet position (he was then serving as minister without portfolio) and declaring that Israel had made “a terrible mistake.”

Mr. Arens’s most enduring political legacy is probably his role in launching the career of Netanyahu, a charismatic furniture salesman — and family friend — whom Mr. Arens hired as his No. 2 after being appointed ambassador to the United States.

In 1992, leaders of the governing Likud party included, from left, Mr. Arens, Ariel Sharon, David Levy and Yitzhak Shamir. (Nattie Harnick/AP)

Likening their relationship to that of a father and son, Mr. Arens helped Netanyahu gain his next posting, as ambassador to the United Nations, and rehired Netanyahu as his deputy while serving as Israel’s foreign minister in the late 1980s.

When Prime Minister Yitzhak Shamir was defeated in the 1992 general election, Mr. Arens was widely considered the front-runner to take his place as leader of Likud.

Instead, Mr. Arens announced that he would step aside, saying he believed in “service, not servitude.” His decision enabled Netanyahu to fill the void in the party’s leadership and win a first term as prime minister in 1996, with Mr. Arens serving as a campaign director.

He staged a short-lived comeback bid just three years later, amid what he described as a “crisis in the Likud,” which had lost several prominent members, but was defeated by Netanyahu and left the Knesset for good in 2003.

“I felt I had done my thing,” Mr. Arens said by way of explanation, according to the Israeli newspaper Haaretz. “Politics was not my profession. It’s not a pleasant job.”

Moshe Arens was born in Kaunas, Lithuania, on Dec. 7, 1925. His mother was a dentist and his father was a businessman. The family lived in Riga, the capital of Latvia, before migrating to New York in 1939, where Mr. Arens attended high school alongside Henry Kissinger. Other classmates included Muriel Eisenberg, whom he later married. In addition to his wife, survivors include four children and nine grandchildren.

As a teenager in New York, Mr. Arens joined Betar, a Zionist youth organization founded by Ze’ev Jabotinsky, who called for a Jewish state on both sides of the Jordan River and served as an ideological lodestar for Menachem Begin and other right-wing Israeli leaders.

Mr. Arens served in the U.S. Army Corps of Engineers during World War II and received a bachelor’s degree from MIT before moving to Israel in 1948, at the outbreak of the country’s war for independence. Against the wishes of his father, he joined the Irgun — inspired to fight for a Jewish state, he said, by the loss of friends and family members during the Holocaust.

In peacetime, he returned to the United States to study at the California Institute of Technology, where he received a master’s degree in aeronautical engineering in 1953 before joining state-owned Israel Aircraft Industries, now known as Israel Aerospace Industries. His work there earned him the Israel Defense Prize in 1971, two years before he was first elected to the Knesset.

Upon retiring, Mr. Arens wrote books including “Flags Over the Warsaw Ghetto” (2009), which highlighted the role members of Betar played in the Warsaw ghetto uprising of 1943. He also worked as a weekly columnist at Haaretz, where he sometimes ventured criticism of his old protege.

Netanyahu, he said, had made a mistake in accepting gifts while in office — behavior that led state prosecutors to recommend that he be indicted on bribery and fraud charges. And the controversial “nation-state” bill, passed in July with Netanyahu’s support, was “a needless law and damaging to Israel,” Mr. Arens wrote.

Still, Mr. Arens remained behind Netanyahu. “Should he leave,” he wrote in March, “it will be difficult to find a replacement of his caliber.”