Share this post: Ask Jack 19: What makes a great leader? In Interviews by The Entourage Today Jack outlines the three defining characteristics the world’s best leaders all possess – vision, mission and values. Do you have a question for Jack? Send it through via the comments, Instagram, Facebook and Twitter! Remember to use the hashtag #AskJackD. Here’s today’s question: What makes a great leader? From Rose Paterson via Facebook. .