R. Chaim was the initiator of a new trend in Talmud study. Possessed of remarkable analytic powers, he would carefully analyze the subject under discussion into its categories and component parts. He evolved a suitable terminology with which to describe the different concepts and showed that the differences in the Talmud itself and among its authoritative interpreters derived from them. The method spread and was adopted in yeshivas throughout the world. Thousands of students flocked to hear him; many of them became distinguished teachers. R. Naphtali Zevi Judah Berlin, head of the yeshiva, would consult him before making any change in its administration. After the Volozhin yeshiva closed in 1892, R. Chaim went to live with his father, the rabbi of Brisk (Brest-Litovsk). His father died that same year and R. Chaim succeeded him. He at once threw himself into communal activity, using his great talents to improve existing religious and social services and to establish new ones. His reputation grew; rabbis and laymen of the surrounding district consulted him on all matters. His opinion was always asked for and heeded, his leadership being taken for granted. He participated in every important rabbinical and communal council. Of a friendly disposition, he kept open house for all, whether Talmudists or scientists, learned or ignorant, religious or irreligious. He was ready to help everyone, sympathizing, comforting, and advising. Scholars would bring him their difficulties; even unmarried mothers came to him for assistance and advice. None left him empty handed and without renewed courage. Most of his salary was given to the needy, and as a result he was frequently in debt. In the winter he left his wood store unlocked so that the poor might help themselves. The lay leaders complained they could not afford the cost involved, but he replied that he would have to instruct his wife not to light his fire since it was impossible for him to sit in a warm room knowing that the poor were freezing.

In 1895 Brisk was swept by a fire which destroyed many homes. All of R. Chaim's energies were devoted toward the rebuilding. He slept in the synagogue porch among those who had lost everything in the fire, and the stream of scholars and lay leaders who wanted to consult him came to him there. Stringent personally in the observance of religious precepts, he was always lenient when applying them to others. In public religious practice, however, he was firm and uncompromising, and did all he could to stem the erosion of Jewish life. Because of his sincerity, great knowledge, and personal piety, he invariably prevailed against those who wished lightly to introduce changes into communal institutions or places of learning.