Kamal Jumblatt was born in 1917 in Moukhtara, in the Chouf area of Lebanon. He was born into the prestigious Jumblatt family, who were traditional leaders of the Lebanese Druze community. The origin of the Jumblatt family is the Kurdish Janpoulad family coming from Shamel Janpoulade and dating back to Janboulad Ibn Kassem al Kirdi al Kaisari, known as Ibn Arabou (1530 – 1580), and governor of Aleppo. His father, the powerful Druze chieftain Fouad Joumblatt, director of the Chouf District, was assassinated on August 6, 1921. After his father’s death, Kamal Jumblatt’s mother Nazira played a significant political role in the Druze community for over a quarter of a century.

In 1926, the young Kamal Jumblatt joined the Lazarus Fathers Institute in Aintoura, where he completed his elementary studies in 1928. He achieved his high school diploma, having studied French, Arabic, science and literature, in 1936, and a philosophy diploma in 1937.

Jumblatt then pursued higher studies in France, where he joined the Faculty of Arts at the Sorbonne University and achieved a degree in Psychology & Civil Education, and another one in Sociology. He returned to Lebanon in 1939, after the outbreak of World War II and continued his studies at Saint Joseph University where he obtained a law degree in 1945.

On May 1, 1948, he married May Arslan, daughter of Prince Shakib Arslan (the Arslans being the other prominent Lebanese Druze family). Their only son, Walid Jumblatt, was born on August 7, 1949.

Kamal Jumblatt practiced law in Lebanon from 1941 to 1942 and was designated the Official State Lawyer for the Lebanese Government. In 1943, he became the leader of the Joumblatt clan after the death of Hikmat Joumblatt, this also brought him into the Lebanese political scene. In September, 1943, Kamal Jumblatt was elected to the National Assembly for the first time, as a deputy of Mount Lebanon. He joined the opposition to the ruling Constitutional Bloc Party, headed by the then President, Bechara El Khoury. In 1946, he was appointed Minister for the first time, for the portfolio of Economy, Agriculture & Social Affairs.

In 1947, in spite of his own election for the second time as deputy, he thought of resigning from the government. He began to believe that change through the Lebanese political system was impossible. After opposition groups attempted to pressure him into leaving he decided to remain in office.

On March 17, 1949, Kamal Jumblatt officially founded the Progressive Socialist Party (PSP) and declared its constitution on May 1, 1949. The PSP was a socialist party espousing secularism and officially opposed to the sectarian character of Lebanese politics. In practice, it has been led and largely supported since its foundation by members of the Druze community in general, and the Jumblatt clan in particular. In the name of the PSP, Jumblatt called the first convention of the Arab Socialist Parties, was held in Beirut in May 1951. The same year, he was reelected for the third time as Deputy of Mount Lebanon.

In 1952, he represented Lebanon at the Cultural Freedom Conference that was held in Switzerland. In August 1952, he organized a National Conference at Deir El Kamar, in the name of the National Socialist Front, calling for the resignation of President Bechara El Khoury. Due mainly to these pressures, the President resigned the same year.

In 1953, Jumblatt was re-elected Deputy for the fourth time. He founded the Popular Socialist Front the same year and led the opposition against the new President, Camille Chamoun. During his presidency, the pro-Western President Chamoun tied Lebanon to the policies of the United States of America and the United Kingdom, who were at that time involved in the creation of the Baghdad Pact, comprising Hashemite Iraq, Turkey and Pakistan. This was seen by pan-Arabists as an imperialist coalition, and it was strongly opposed by the influential Nasserist movement. Jumblatt supported Egypt against an attack by Israel, France, and the United Kingdom in the Suez War of 1956, while Chamoun and parts of the Maronite Christian elite in Lebanon tacitly supported the invasion. The sectarian tensions of Lebanon greatly increased in this period, and both sides began to brace for violent conflict.

In 1956, Jumblatt failed for the first time in the parliamentary elections, complaining of electoral gerrymandering and election fraud by the authorities. Two years later, he was one of the main leaders of a major political uprising against Camille Chamoun's Maronite dominated government, which soon escalated into street fights and guerilla attacks. While the revolt reflected a number of political and sectarian conflicts, it had a pan-Arabist ideology, and was heavily supported through Syria by the newly formed United Arab Republic. The uprising ended after the United States intervened on the side of the Chamoun government and sent the U.S. Marine Corps to occupy Beirut. A political settlement followed by which Fuad Chehab was appointed new President of the Republic.

Jumblatt chaired the Afro - Asian People’s Conference in 1960 and founded the same year, the National Struggle Front (NSF) (جبهة النضال الوطني), a movement which gathered a large number of nationalist deputies. That same year, he was reelected Deputy for the fifth time and the NSF won 11 seats within the Lebanese Parliament. From 1960 to 1961 he was Minister for the second time, for the National Education portfolio and then in 1961 he was appointed Minister of Public Work & Planning. From 1961 to 1964 he was Interior Minister.

On May 8, 1964, he won at the parliamentary elections for the sixth time. In 1965, he began joining together Arab nationalist and progressivist politicians into a Nationalist Personalities Front. In 1966 he was appointed Minister of Public Work and Minister of PTT. He also represented Lebanon at the Congress of Afro - Asian Solidarity, and presided over the parliamentary and popular delegation to the People’s Republic of China in 1966.

He supported the Palestinians in their struggle against Israel for ideological reasons, but also to garner support from the Palestinian fedayeen based in Lebanon's refugee camps. The presence in Lebanon of large numbers of Palestinian refugees was resented by most Christians, but Jumblatt strived to build a hard core of opposition around the Arab nationalist slogans of the Palestinian movement. Demanding a new Lebanese order based on secularism, socialism, Arabism and an abolition of the sectarian system, Jumblat began gathering disenchanted Sunnis, Shi'a and leftist Christians into an embryonic national opposition movement.

On May 9, 1968 he was reelected Deputy for the seventh time. In 1970, he was once again appointed Minister of the Interior, a reward for his last minute switch of allegiance in the presidential election that year, which resulted in Suleiman Franjieh's victory by one vote over Elias Sarkis, who was considered the odds - on favourite. As Interior Minister, he legalized the Communist Party (LCP) and the Syrian Social Nationalist Party (SSNP). In 1972, Kamal Jumblatt was awarded the Lenin Peace Prize by the Soviet Union. The same year, he was reelected Deputy for the eighth time. The following year, he was unanimously elected Secretary General of the Arab Front, a movement supportive of the Palestinian revolution.

The 1970s in Lebanon were characterized by rapidly building tension between the Christian dominated government and Muslim and leftist opposition forces, demanding better representation in the government apparatus and a stronger Lebanese commitment to the Arab world. The conflict took place more or less along the same sectarian and political lines as the 1958 rebellion.

Both the opposition and their mainly Christian opponents organized armed militias, and the risk of armed conflict increased steadily. Jumblatt had organized his own PSP into an armed force, and made it the backbone of the Lebanese National Movement (LNM), a coalition of left wing Lebanese demanding the abolition of the sectarian quota system that permeated Lebanese politics, which discriminated against Muslims. The LNM was further joined by Palestinian radicals of the Rejectionist Front, and maintained good relations with the officially non-committal Palestine Liberation Organization (PLO). The Palestinian presence in the ranks of the opposition was a new development compared to the 1958 conflict.

In April 1975, a series of tit-for-tat killings culminating in a Phalangist massacre of Palestinian guerillas, prompted full blown fighting in Beirut. In August 1975, Jumblatt declared a program for reform of the Lebanese political system, and the LNM openly challenged the government's legitimacy. In October a new round of fighting broke out, and quickly spread throughout the country: the Lebanese Civil War had begun.

During the period of 1975 - 1976 Jumblatt acted as the main leader of the Lebanese opposition in the war, and with the aid of the PLO the LNM rapidly gained control over nearly 70% of Lebanon. This prompted Syrian intervention, since the Assad regime feared a collapse of the Christian dominated order. Some 40,000 Syrian soldiers invaded Lebanon in 1976 and quickly smashed the LNM's favorable position; a truce was declared and the fighting subsided. The conflict remained unsolved, however, and during 1977, violence again began to increase.

On March 16, 1977, Kamal Jumblat was assassinated. Prime suspects include the pro-Syrian faction of the Lebanese Syrian Social Nationalist Party (SSNP), in collaboration with the Ba'ath Party. In 2005, his son Walid Jumblatt, who immediately succeeded him as the main Druze leader of Lebanon and as head of the PSP, became the closest ally the Syrians had in Lebanon. In June 2005, former secretary general of the Lebanese Communist Party George Hawi claimed in an interview with al Jazeera, that Rifaat al-Assad, brother of Hafez al Assad and uncle of Syria's current President Bashar al-Assad, had been behind the killing of Jumblatt. It is widely believed in Lebanon that Syria was also behind Hawi's death in a car bomb, some days later.

Extremely literate, Kamal Jumblatt lectured extensively and wrote more than 1200 editorials in both Arabic and French.