To prevent any more civil wars within the Legion from occurring, a council will be established. A council of steel.
—A Legion leader during the Council's formation
When Ferd Swqaru, leader of the Legion, died of old age in 97 ABY, he failed to choose a successor, and as a result the Legion quickly splintered into different factions led by members of its inner circles, each believing itself to be the true heir to the Legion.
However, one faction purchased a large supply of battle droids from the original leader of the Legion, Unit 8311, and bested the other factions, reunifying the Legion. During the reunification of the Legion, the faction leaders agreed to form a council to prevent any more civil wars from occurring.
Unlike most non-government councils, the Legion Council was quite fast in making decisions, mainly as its members had been indoctrinated into thinking similarly during their rise through the ranks of the Legion, although its members would come into conflict over important issues.
The council would rule the Legion during the time of the New Empire and Darth Krayt, where it would become more split as members debated over the best course of action for the Legion in the new galaxy.
The membership of the Council rarely changed during its initial existence. Most of its members consisted of leaders or representatives of the old Legion splinter factions.