It's a bit difficult, but still possible, to deduce a consistent philosophy about leadership from Tolstoy's fiction. But are we speaking of military or political leadership or just the general leadership qualities one needs in ordinary life? Several examples in the novels might be considered in our approach to these different ramifications of your question.
In War and Peace, the main leaders, both political and military, are Napoleon on the one side and Czar Alexander I on the other. Both men are flawed, but unsurprisingly, since much of the novel is an expression of Russian national feeling, Alexander emerges as the greater leader. Tolstoy makes a distinction between leadership that seeks power alone (Napoleon) and the initially inexperienced Alexander who learns from his mistakes and finally, in 1812, realizes that an outside force—the invading French—must be resisted at any cost.
Napoleon ultimately is an inadequate commander because he believes in nothing but his own ambition. Alexander, though a royal born to privilege and principally of non-Russian descent, becomes the true representative of the Russian people, and this is the quality of leadership Tolstoy values in him. Similarly, Marshal Kutuzov, who led the Russians to victory in 1812, is depicted positively by Tolstoy despite the negative portrayals of him by some historians. After taking enormous losses at the battle of Borodino, Kutuzov kept the army together, and his refusal to give up even under apparently hopeless conditions ultimately led to the defeat of the invading French.
Lest anyone think Tolstoy's views were based totally on nationalism, his portrayal in his novella Hadji Murat of Alexander's successor, Nicholas I, was negative in the extreme. Nicholas is shown as an amoral womanizer and a leader who orders an almost genocidal policy against the Caucasus Muslim people. For Tolstoy, war was justifiable as self-defense, but these efforts to conquer outside peoples were wrong. Nicholas was essentially doing the same thing to the Chechens as Napoleon had done to Russia.
What of the question of "leadership" not in large-scale political or military actions but in daily life? Tolstoy judges men, in peacetime and in domestic settings, by a similar standard. In Anna Karenina, Anna's husband, Karenin, is supposed to be a brilliant man in his high-level government post, but in his personal life he appears a passive individual who shows no feeling for his wife and loses her. This lack of assertiveness on Karenin's part is a kind of peacetime opposite to the positive qualities of leaders in the military and political milieu.
When Karenin is told that another man whose wife had left him had then challenged the wife's lover to a duel and shot him, Karenin is terrified that the same action will be expected of him. "Physically he was a coward and had no familiarity with firearms," Tolstoy tells us of Karenin. This contrasts with Anna's lover, Vronsky, and other male characters in the novel. Like Hemingway, Tolstoy celebrates the standard "masculine" virtue of physical courage. He is a "male chauvinist"—but unsurprisingly so for the period in which he lived. We can judge his overall views on leadership flawed but consistent and typical of his time and place.