In the aftermath of the June–September 1982 Israeli invasion of Lebanon, President Amin Gemayel, convinced that a strong and unified national defense force was a prerequisite to rebuilding the nation, announced plans to raise a 60,000-man army organized into twelve brigades (created from existing infantry regiments), trained and equipped by France and the United States.

The Brigade also fielded a logistics battalion, equipped with US M151A2 jeeps, Land-Rover long wheelbase series III, Chevrolet C20 and Dodge Ram (1st generation) pickups and US M35A2 2½-ton military trucks.

[14] Headquartered at the Sayyad Roundabout Barracks in the Hazmiyeh district of east Beirut, the brigade was initially commanded by Colonel Mounir Merhi, replaced in 1984 by Col. Ghassan Ged, a Greek Orthodox.

Commanded by Colonel Mounir Merhi, the 9th Brigade during the Mountain War was deployed at the Hazmiyeh and Sin el Fil eastern suburbs of Beirut.

[18] Regarded as being totally loyal to General Michel Aoun's interim military government, the majority of the brigade's battalions – except one (92nd), deployed at the Port district – were placed along the Hazmiyeh sector of the Green Line, where they fought successfully the Lebanese Forces (LF) militia faction led by Elie Hobeika during his failed coup attempt to seize control of east Beirut on January 16, 1986.