As the most prominent pro-Israel militia in Israeli-occupied Lebanon, the SLA frequently engaged in armed clashes with Hezbollah, the Palestine Liberation Organization, and other militant groups.

In 1975, at the town of Marjayoun in the Jabal Amel region of southern Lebanon, some local 300 Kataeb Regulatory Forces (KRF) and Guardians of the Cedars (GoC) militiamen were mustered together into the so-called "Free Lebanese Militia" – FLM (Arabic: Al-Milishia Al-Lubnaniyyat Al-Hura), ostensibly formed to defend the nearby Christian towns of Kfar Falous, Jezzine, Qlaiaa, Ain Ebel, Rumeish and surrounding villages threatened by Palestine Liberation Organization (PLO) and later by Lebanese Arab Army (LAA) attacks.

[4][5][6] By late 1976, pressure from PLO and LNM-LAA militias finally forced Major Saad Haddad to evacuate the town and withdraw unopposed with his battalion to the village of Qlaiaa, close to the border with Israel.

Here Maj. Haddad and his men placed themselves under the protection of the Israel Defense Forces (IDF),[6] eventually providing the cadre – after merging with the local Christian FLM, Shia Muslim and Druze militias, gathered since October 21, 1976, into the informal "Army for the Defense of South Lebanon" or ADSL (French: Armée de Défense du Liban-Sud or ADLS)[7] – of the so-called "Free Lebanese Army" (FLA), formed in March 1978 under the auspices of another AMAN officer, reserve Major Yoram Hamizrachi.

[8][9] Primarily based at the towns of Marjayoun and Qlaiaa in southern Lebanon, and provisionally headquartered at the Hotel Arazim in Metula, Israel, the 1,200-strong FLA/SLA was initially placed under the overall command of Hamizrachi himself.

The new FLA fought against various groups including the Palestine Liberation Organization (PLO), the Amal Movement and (after the 1982 Israeli invasion of Lebanon) the emerging Hezbollah.

The SLA hosted the Christian radio station Voice of Hope (established and funded by George Otis, founder of High Adventure Ministries).

Beginning in 1982, the SLA played host to Middle East Television (which was also established, funded, and operated by High Adventure Ministries).

Israel denies any involvement, and claims that Khiam was the sole responsibility of the SLA; this has been contested by human rights organizations such as Amnesty International.

Ehud Barak's Labor Party pledged during his March 1999 election campaign for Prime Minister to withdraw Israeli troops from Lebanon by July 2000.

Retreating SLA members and their families commandeered empty houses in Marjayun, Ibl al-Saqi and Kawkaba in the Indian UNIFIL zone.

[21] The next day, SLA forward positions in the eastern sector collapsed and Israeli forces began their general withdrawal from the remaining areas of the security zone.

The withdrawal was complete on Wednesday, May 24, 2000; the sight of Saad Haddad's statue being dragged through the streets of the Lebanese town of Marjayoun was a sure sign that the South Lebanon Army was gone.

Many were terrified of being captured (and possibly killed) by Hezbollah guerrillas or vengeful mobs, or being jailed or executed by the Lebanese government.

Israeli prime minister Ehud Barak was criticized in Israel by the Jewish settler movement on the grounds that his decision to withdraw without consulting his SLA allies led to the speed and confusion of its collapse.

[25] Of those who initially fled to Israel, many SLA members and their families eventually chose to return to Lebanon after Hezbollah promised they would not be harmed.

On April 6, 2006, the Israeli Knesset Finance Committee approved the payment of 40,000 shekels per family to SLA veterans, payable over seven years.

[citation needed] This force manned 46 locations along the front (from Naqoura in the west to the eastern slopes of Mount Hermon), while the Israeli Army had 11 centers, mostly in the rear lines.