Self-discipline is nothing but self-consciousness. Internally, Self Discipline is about disciplined thoughts. Thoughts are single pointed and focused to whatever you do. We experience all kinds of situations good and bad in our lives that require moral courage to deal with. Self-discipline is what supports that moral courage and allows us to act in a right manner. Self-disciplined people have better clarity of thoughts and, therefore, do not get carried away by the herd mentality. They may exercise restraint while expressing emotions or may avoid indulgence because of better control over self / clarity of thoughts and not because of any weakness.
A self-disciplined mind has more awareness of the thoughts and actions. Awareness is at the level of the energetic connection between Heart and Mind. Self-discipline is to deal with both positive and negative feelings or experiences with much more awareness of your own being and actions and thoughts. You sense yourself and that's all you need to let your thoughts and behavior work to guarantee you a balanced life. Without discipline, you do not manage to transform negative habits and you do not create a new state of awareness where the self is nourished through the experience of positivity.
Self-disciplined people are more influential because more often they can harmonize their mind, their heart, and their action, to put simply, walk the talk. People are still drawn toward highly disciplined people. People like the stability of knowing that a person they are following is consistent and reliable. These things must come from a disciplined mind and actions. Hence, discipline reflects one’s EQ and it’s a leadership quality.