The Enchantress is unusual for a (former) member of the Inner Circle in one significant way; she firmly believes she is doing the right thing. She is worshiped across the Disney multiverse by those who share her philosophy that the ends always justify the means. Aside from fending off attempts by Queen Grimhilde to thwart her out of jealousy, The Enchantress never involved herself in the politics of the Inner Circle. The other members, she reasons, will be punished for their evil deeds after they've finished helping her punish those who the High Council won't take the necessary measures to punish.
Initially, she used to be one of the members of the High Council. But her lessons were harsher than the others, and she was petty and vengeful. This lead to many reprimands from Zeus, and she became bitter. The Friends saw an opportunity, and with Forte's help, tipped her off about the Prince's selfishness. Her curse on the castle was the final straw, leading to her being expelled from Zeus' ranks - and directly into the waiting arms of the Friends. She's not only a powerful member of Chernabog's ranks, she's the only one with inside knowledge of Zeus' doings. However, the Friends's approach to things eventually felt primitive and counter-intuitive to her and she realized that they were only about pain and suffering. Ever since, she has been a neutral figure wanting to just end it all, with her as the sole figure of morality.
Her Kingdom Hearts counterpart, on the other hand, stayed with the High Council.