Moshe Dayan was born on Kibbutz Degania Alef near the shores of Lake Kinneret (Sea of Galilee) in pre-Mandate Palestine. His parents were Shmuel and Devorah, Jewish immigrants from Ukraine. He was the second child to be born on the kibbutz (after Gideon Baratz). He was named Moshe after Moshe Barsky, the first member of the kibbutz to be killed in an Arab attack. Soon after, his parents moved to Nahalal, the first Moshav to be established. He attended the Agricultural School there. At the age of 14, he joined the newly formed Jewish militia known as the Haganah. In 1938 he joined the Palestine Supernumerary Police and became a motorized patrol ("MAN") commander. One of his military heroes was the British pro-Zionist officer Orde Wingate, under whom he served in several Special Night Squads operations. He was arrested by the British in 1939 (when the Haganah was outlawed), but released after two years in February 1941, as part of Haganah cooperation with the British during World War II. Dayan was assigned to a small Australian - Palmach - Arab reconnaissance task force, formed in preparation for the Allied invasion of Syria and Lebanon and attached to the Australian 7th Division. Using his home kibbutz of Hanita as a forward base, the unit frequently infiltrated Vichy French Lebanon, wearing traditional Arab dress, on covert surveillance missions.

On 7 June, the night before the invasion, the unit crossed the border and secured two bridges over the Litani River. When they were not relieved as expected, at 04:00 on 8 June, the unit perceived that it was exposed to possible attack and — on its own initiative — assaulted a nearby Vichy police station, capturing it in a firefight. A few hours later, as Dayan was using binoculars they were struck by a French bullet, propelling metal and glass fragments into his left eye and causing it severe damage. Six hours passed before he could be evacuated and Dayan lost the eye. In addition, the damage to the extraocular muscles was such that Dayan could not be fitted with a glass eye, and he was forced to adopt the black eyepatch that became his trademark.

In the years immediately following, the disability caused him some psychological pain. Dayan wrote in his autobiography: "I reflected with considerable misgivings on my future as a cripple without a skill, trade, or profession to provide for my family." He added that he was "ready to make any effort and stand any suffering, if only I could get rid of my black eye patch. The attention it drew was intolerable to me. I preferred to shut myself up at home, doing anything, rather than encounter the reactions of people wherever I went."

Ruth Dayan, his first wife, divorced Moshe in 1971 after 36 years of marriage due to his numerous extramarital affairs. In the Israeli best selling book that followed the divorce, Or Did I Dream The Dream?, she wrote a chapter about "Moshe's bad taste in women." Their daughter, Yael Dayan, a novelist, is best known in Israel for her book, My Father His Daughter  about her relationship with her father. She followed him into politics and has been a member of several Israeli leftist parties over the years. She has served in the Knesset and on the Tel Aviv City Council, and is the current Deputy Mayor of Tel Aviv/Jaffa, responsible for social services. One of his sons, Assi Dayan, is an actor and a movie director. Another son, novelist Ehud Dayan, who was cut out of his father's will, wrote a book critical of his father after Dayan died, mocking his military, writing, and political skills and calling him a philanderer. Following his divorce from first wife Ruth, Dayan remarried.

In 1947, Dayan was appointed to the Haganah General Staff working on Arab affairs, in particular recruiting agents to gain information about irregular Arab forces in Palestine. His brother, Zorik, was killed in fighting, 14 April 1948. A month later, 18 May, Dayan was given command of the Jordan Valley sector and his troops stopped the Syrian advance South of the Sea of Galilee. In June he became the first commander of the 89th Battalion, part of Sadeh's Armoured Brigade.

On 20 June 1948, two men from one of his companys were killed in a confrontation with Irgun members trying to bring weapons ashore from the Altalena at Kfar Vitkin. During Operation Danny he led his Battalion in a brief raid through Lod in which nine of his men were killed. His Battalion was then transferred to the South where they captured Karatiya, close to Faluja, 15 July. On 23 July he was appointed Military Commander of Jerusalem. In the autumn he was involved in negotiations with Abdullah el Tell, the Jordanian Military Commander of East Jerusalem, over a lasting cease-fire for the Jerusalem area. The following year, 1949, he had at least five face to face meetings with King Abdullah of Jordan over the Armistice Agreement and the search for a longer term peace agreement. Despite being involved in these negotiations Dayan was recommending to Ben Gurion, in September 1949, that the army should be used to open the road to Jerusalem and to gain access to the Western Wall. On 25 October 1949 he was promoted to Major - General and appointed commander of the Southern Command. Most of the staff officers resigned in protest of his replacement of the previous commander, Yigal Allon.

After the 1948 war Dayan, a Ben Gurion loyalist, began to rise rapidly through the ranks and in 1950 held the position of GOC Southern Command. During this time he ordered the destruction of a number of Muslim holy sites. From 1953 to 1958, he was the
Chief of Staff of the Israel Defense Forces. In this capacity, he personally commanded the Israeli forces fighting in the Sinai during the 1956 Suez Crisis. It was during Dayan's tenure as Chief of Staff that he delivered his famous eulogy of Roi Rutenberg, a young Israeli killed in 1956.

On taking over command, based on Ben-Gurion's three year defence programme, Dayan carried out a major reorganisation of the Israeli army which, among others, included: Strengthened combat units at the expense of administrative 'tail'. Raising the Intelligence and Training Branches of the Israeli Army. Surrendering the activities of stores and procurement to the civilian Ministry of Defense. Revamping the mobilisation scheme and ensuring earmarking for adequate equipment. Starting a military academy for officers of the rank of major and above. Emphasised strike forces (Air Force, Armour) and on training of Commando battalions. Developed GADNA, a youth wing for military training.

Moshe Dayan was covering the Vietnam War to observe modern warfare up close after his political life. In fact, he was on patrol as an observer with members of the US Marines Corps. Although Dayan did not take part in most of the planning before the Six-Day War of June 1967, his appointment as defense minister contributed to the Israeli success. He personally oversaw the capture of East Jerusalem during the 5 June - 7 June fighting. During the years following the war, Dayan enjoyed enormous popularity in Israel and was widely viewed as a potential Prime Minister. At this time, Dayan was the leader of the hawkish camp within the Labor government, opposing a return to anything like Israel's pre 1967 borders. He once said that he preferred Sharm-al-Sheikh (an Egyptian town on the southern edge of the Sinai Peninsula overlooking Israel's shipping lane to the Red Sea via the Gulf of Aqaba) without peace to peace without Sharm-al-Sheikh. He modified these views later in his career and played an important role in the eventual peace agreement between Israel and Egypt. In 1997, years after Dayan died, an Israeli journalist, Rami Tal, published conversations he had with Dayan in 1976. In that conversation Dayan claimed that 80 percent of the cross-border clashes between Israel and Syria in the years before the war were a result of Israeli provocation (Dayan was not Defense minister at the time). He confessed:

I know how at least 80 percent of the clashes there started. In my opinion, more than 80 percent, but let's talk about 80 percent. It went this way: We would send a tractor to plough someplace where it wasn't possible to do anything, in the demilitarized area, and knew in advance that the Syrians would start to shoot. If they didn't shoot, we would tell the tractor to advance farther, until in the end the Syrians would get annoyed and shoot. And then we would use artillery and later the air force also, and that's how it was.

Also, later, he regretted it as:

I made a mistake in allowing the Israel conquest of the Golan Heights. As defense minister I should have stopped it because the Syrians were not threatening us at the time [fourth day of the war].

He also portrayed the desire of the residents in the Kibutzim beneath the Golan Heights that they be captured as stemming from the desire for their agricultural land and not primarily for security reasons. This description was hotly denied by the Kibutz leaders (the Hula Valley kibutzim did not get any land on the Golan). Dayan's contention was denied by Muky Tsur, a longtime leader of the United Kibbutz Movement who said "For sure there were discussions about going up the Golan Heights or not going up the Golan Heights, but the discussions were about security for the kibbutzim in Galilee," he said. "I think that Dayan himself didn't want to go to the Golan Heights. This is something we've known for many years. But no kibbutz got any land from conquering the Golan Heights. People who went there went on their own. It's cynicism to say the kibbutzim wanted land." About Dayan's comments, Israeli ambassador to the United States Michael Oren says

"There is an element of truth to Dayan's claim, but it is important to note that Israel regarded the de-militarized zones in the north as part of their sovereign territory and reserved the right to cultivate them — a right that the Syrians consistently resisted with force. Syria also worked to benefit from the Jordan river before it flowed into Israel, aiming to get use of it as a water source; Syria also actively supported Palestinian resistance movements against Israel. Israel occasionally exploited incidents in the de-militarized zones to strike at the Syrian water diversion project and to punish the Syrians for their support of the Palestinian resistance. Dayan's remarks must also be taken in context of the fact that he was a member of the opposition at the time. His attitude toward the Syrians changed dramatically once he became defense minister. Indeed, on June 8, 1967, Dayan bypassed both the Prime Minister and the Chief of Staff in ordering the Israeli army to attack and capture the Golan."

After Golda Meir became Prime Minister in 1969 following the death of Levi Eshkol, Dayan remained Minister of Defense. He was still in that post when the Yom Kippur War began catastrophically for Israel on 6 October 1973. As the highest ranking official responsible for military planning, Dayan may bear part of the responsibility for the Israeli leadership having missed the signs for the upcoming war. In the hours preceding the war, Dayan chose not to order a full mobilization or a preemptive strike against the Egyptians and the Syrians. He assumed that Israel would be able to win easily even if the Arabs attacked and, more importantly, did not want Israel to appear as the aggressor, as it would have undoubtedly cost it the invaluable support of the United States (who would later mount a massive airlift to rearm Israel, a major turning point of the war).

Following the heavy defeats of the first two days, Dayan's views changed radically; he was close to announcing "the downfall of the "Third Temple" at a news conference, but was forbidden to speak by Meir. Dayan further backed from high level political role, and turned publicly as symbol for Israel independence and hope for a Third Temple to be built.

Dayan suggested options at the beginning of the war, including a plan to withdraw to the Mitleh mountains in Sinai and a complete withdrawal from the Golan Heights in order to carry the battle over the Jordan, abandoning the core strategic principles of Israeli war doctrine, which says that war must be taken into enemy territory as soon as possible. The Chief of Staff, David Elazar, objected to these plans and was proved correct. Israel broke through the Egyptian lines on the Sinai front, crossed the Suez canal, and encircled the 3rd Egyptian Army. Israel also counterattacked on the Syrian front, successfully repelling the Jordanian and Iraqi expeditionary forces and shelling the outskirts of Damascus, ending the war on favorable terms.

According to those who knew him, the war deeply depressed Dayan. He went into political eclipse for a time. In 1977, despite having been re-elected to the Knesset for the Alignment, he accepted the offer to become Foreign Minister in the new Likud government led by Menachem Begin. He was expelled from the Alignment, as a result and sat as an independent MK. As foreign minister in Begin's government, he was instrumental in drawing up the Camp David Accords, a peace agreement with Egypt. Dayan resigned his post in October 1979, because of a disagreement with Begin over whether the Palestinian territories were an internal Israeli matter (the Camp David treaty included provisions for future negotiations with the Palestinians; Begin, who didn't like the idea, did not put Dayan in charge of the negotiating team). In 1981 he founded a new party, Telem.

Telem won two seats in the 1981 elections, but Dayan died shortly thereafter, in Tel Aviv, from a massive heart attack. He had been in ill-health since 1980, after he was diagnosed with colon cancer late that year. He is buried in Nahalal in the moshav (a collective village) where he was raised. Dayan willed his personal belongings to his bodyguard. In 2005, his eye patch was offered for sale on Ebay with a starting bid of $75,000 U.S. dollars.

Dayan was a complex character; his opinions were never strictly black and white. He had few close friends; his mental brilliance and charismatic manner were combined with cynicism and lack of restraint. Ariel Sharon noted about Dayan:

He would wake up with a hundred ideas. Of them ninety-five were dangerous; three more were bad; the remaining two, however, were brilliant.

Dayan combined a kibbutznik's secular identity and pragmatism with a deep love and appreciation for the Jewish people and the land of Israel -- but not a religious identification. In one recollection, having seen rabbis flocking on the Temple Mount shortly after Jerusalem was captured in 1967, he asked "what is this? Vatican?" Dayan later ordered the Israeli flag removed from the Dome of the Rock, and gave administrative control of the Temple Mount over to the Waqf, a Muslim council. Dayan believed that the Temple Mount was more important to Judaism as a historical rather than holy site.

Dayan was also an author and an amateur archaeologist, the latter hobby leading to some controversy as his amassing of historical artifacts, often with the help of his soldiers, broke a number of laws. Dayan's habit of pilfering newly discovered archaeological sites, before arrival of the Antiquities Authority and State authorized archaeologists, once almost cost him his life and left him with a slight permanent impairment. Shortly after the Six-Day War Dayan heard of a new archaeological find near Holon, due south of Tel Aviv. Not wanting to arouse suspicion, he entered the dig alone, and started to look for artifacts, when suddenly the entire dig caved in upon him, burying him alive. Only a hand remained visible. Shortly thereafter, a group of playing kids passed and saw a human hand protruding from the caved-in hole in the ground. They managed to dig him out alive, but due to possible oxygen deficiency in his brain, he remained with a speech impairment during the rest of his life, as well as with a partially paralyzed hand. Upon his death, his extensive archaeological collection was sold to the state.