His young adulthood is best summed up with his own words from his book Confession:

I cannot recall those years without horror, loathing, and heart-rending pain. I killed people in war, challenged men to duels with the purpose of killing them, and lost at cards; I squandered the fruits of the peasants' toil and then had them executed; I was a fornicator and a cheat. Lying, stealing, promiscuity of every kind, drunkenness, violence, murder - there was not a crime I did not commit...Thus I lived for ten years."

In 1851 Tolstoy went to visit his brother, an Army officer stationed in the Caucasus mountains, and ended up joining the army himself. In the Caucasus, he came into contact with cossacks, and later focused on them in one of his best shorter novels, The Cossacks (1861). Between battles with the hill tribes, Tolstoy completed an three autobiographical novels: Childhood (1852), Boyhood (1854), Youth (1855-57), which drew on the psychologically significant memories common to all growing boys. These works received instant acclaim, as did Sebastopol (1854-55), based on Tolstoy's experiences in the Crimean War.

Tolstoy returned to Saint Petersburg in 1856 and became interested in the education of peasants. While on trips abroad (1857 and 1861), he visited French and German elementary schools, and at Yasnaya Polyana he started a village school that, in its teaching methods, foreshadowed the tenets of modern education. In 1862 the novelist married Sonya (Sofya) Andreyevna Bers, a member of a cultured Moscow family. In the next 15 years he raised a large family, successfully managed his estate, and wrote his two greatest novels: War and Peace (1864-69) and Anna Karenina (1873-76). His other major novels include Father Sergius (1898), Resurrection (1899), and Hadji Murat (1904). He wrote many short stories, some of which are contained in The Kreutzer Sonata (1889) and others, some of which have been reprinted in the volume entitled Twenty-Three Tales (1907). In addition he wrote several plays and numerous religious and educational books, essays, and tracts.

Later in life, Tolstoy formulated a unique Christian philosophy which espoused non-resistance to evil as the proper response to aggression, and which put great emphasis on fair treatment of the poor and working class. Tolstoy also gave a strong plea for Christians to reject the State when seeking answers to questions of morality and instead to look within themselves and to God for their answers.

Tolstoy's books Confession (1882), What Then Must We Do? (1886), and most notably The Kingdom of God is Within You (1894) clearly outline his radical and well-reasoned revision of traditional Christian thinking. The Kingdom of God is Within You inspired Gandhi with the idea of non-resistance to evil. The Death of Ivan Ilyich (1886) and Master and Man (1895), both depict the spiritual conversion of a man facing death. Resurrection (1899), is the story of the moral regeneration of a conscience-stricken nobleman.

At the age of 82, increasingly tormented by the disparity between his teachings and his personal wealth, and by endless quarrels with his wife, who resisted his attempts to renounce their material possessions, Tolstoy left his home one night. He fell ill three days later and died on November 20, 1910, at a remote railroad station. He was hailed as a uniquely powerful moral force throughout the world and a source of inspiration to many.

• Confession (1882)
• The Death of Ivan Ilyich (1886)