Do you care about about Military history, do you need know about Military history in-order to be an effective Leader?

History is Context. Context is essential for Critical thought and Decision Making, which are Leadership skills. Military History is just a tailored version, providing specialized context, which in turn grants better insight when applied to leadership skills.

I would say yes; you do need to know history in order to be a better leader. It helps you know exactly why certain things are done the way they are. We as military professionals stand on the shoulders of giants. In the promotion board, both NCO history and Army history was hit on pretty hard as it I think it should be at all boards. When a few of my soldiers went to a board specifically for intelligence specialists, they were focused a lot on actual intelligence doctrine and publications but once they got there they were blindsided by a lot of questions about famous past intelligence professionals both in the military and out. (If you're doing it right, you talk to more than just other Army intel guys- you talk to people throughout the Intelligence Community such as the CIA, DIA, NGA, NGIC as well as the other military services.)
I'm not saying you need to have a degree in American or world history or that knowledge by itself makes you a better leader than someone else who may be more technically proficient, but it goes a long way.