Leadership was the capacity of an individual to be a leader. Additionally, leadership was either a group of leaders or the office of a leader.
In 2365, the command crew of the USS Enterprise-D gathered to discuss the education of acting ensign Wesley Crusher in the absence of his mother, Doctor Beverly Crusher. To this end, Commander William T. Riker wanted to put Crusher in charge of the vessel's planetary mineral surveys, though Doctor Katherine Pulaski worried that this would be a big job for him with a lot of responsibility. Lieutenant Geordi La Forge noted that Crusher would require a team and that it took command presence to lead, wondering if he was ready for this. To this, Counselor Deanna Troi replied that leadership grew from self-confidence, something which was part of a Starfleet officer's education. (TNG: "Pen Pals")
In 2366, a group of aliens chose to study the concepts of authority and leadership by kidnapping individuals of various species and replacing them with doppelgängers. The doppelgänger who replaced Jean-Luc Picard as captain aboard the Enterprise-D studied authority and leadership by pushing the vessel to the brink of disaster and seeing how far its crew was willing to go before no longer following orders. Once the ruse was discovered, the real Captain Picard asked the aliens why they had chosen to study these concepts. They replied that they had no such concepts, that as they were all equal, such distinctions among them were meaningless and they therefore wished to study the nature of command. (TNG: "Allegiance")
In 2372, the crew of the USS Voyager was forced to abandon the vessel's captain, Kathryn Janeway, and commander, Chakotay, on a planet dubbed "New Earth" when both contracted a rare viral infection that could seemingly only be counteracted by an unknown element found on the planet itself. To this end, they ordered the crew to abandon them on the planet and also ordered to not risk contacting the Vidiians, despite the possibility that they could provide a cure. Tuvok was left as captain in Janeway's place and chose to follow these orders. After over three weeks away, however, the crew was distraught at the loss to the point of near-mutiny. When Tuvok threatened to permanently relieve Harry Kim of duty for questioning his orders, Kes, whom Tuvok considered a valued friend, took Tuvok aside for a private chat. She reminded him that he was responsible not just for the crew's physical well-being, but also their emotional well-being. Though Tuvok believed he could not be held hostage to the crew's feelings, as they talked further, he saw the wisdom of Kes's words. He returned to the crew, telling them that while he believed that in general it demonstrated faulty leadership to be guided by the emotions of a distraught crew, as captain he could not ignore the sensibilities of those he commanded. He then ordered that they set course for a Vidiian convoy, stating that he would take full responsibility for the decision. (VOY: "Resolutions")
In 3189, Ensign Sylvia Tilly thanked Captain Saru for a private meal with the bridge crew. Although the meal ended badly, Tilly believed it had a positive outcome. In her words, "Sir, we made a decision together, and we are living with it together. The fact that you reminded us of that and reminded us who we are to each other, that...I think that's leadership." (DIS: "Forget Me Not")
Later that year, the topic of leadership arose in another conversation between Tilly and Saru. He wanted her as his acting first officer until a permanent replacement could be found. During his attempt to persuade her into accepting the promotion, Saru said, "Part of leadership is the acknowledgement that one is suited to it." (DIS: "Unification III")
In 3190, Captain Michael Burnham and Federation President Laira Rillak discussed leadership and the Kobayashi Maru scenario following the death of three individuals in the catastrophe of Deep Space Repair Beta Six. Burnham had wanted to save everyone on board the station and Rillak felt that part of leadership was accepting there were certain things beyond one's control. She told Burnham that "Leadership is about balance. Knowing what weight is yours to carry and what isn't. You just don't see that yet." (DIS: "Kobayashi Maru")