He was an enigmatic Orthodox scholar and rabbi who pioneered a new way of educating the old-time Orthodox yeshiva students of Talmud stressing ethics (mussar) in Eastern Europe . He was orphaned at an early age , and not much is known about his formative years.
His motto was summed up in the words Gadlut Haadam - the "Greatness of Man". He stressed the need for mussar using works such as those of Rabbi Moses Chaim Luzzato, polishing the character traits of his students so that they would aspire to become gedolim - "great ones" in all areas of both scholarship, and personal ethics .
This new emphasis on ethics as a separate subject to Talmud was opposed by many of his contemporaries. They argued that pure focus on the Talmud would automatically create greatness in both scholarship and ethics. But Rabbi Finkel believed that, that was true in previous generations. The modern age was different. Too many new ideologies such Socialism and Zionism and the lure of universities that were opening their doors to young Jews, were all attracting the young away from Judaism . He was determined to prove that what he had to offer was just as appealing as anything the outside world could offer up.
His main opponents in the yeshiva world were the members and alumni of the Brisk yeshiva of Lithuania headed by the Soloveitchik family, who, unlike their kin Joseph Soloveitchik, were adamantly opposed to any changes in what they believed to be the time-tested ways of yeshiva education. To this day, their yeshivot based mainly in Jerusalem today, do not teach mussar ethics as some sort of special curriculum.
He spent ten out of every twelve months with his students full time, only returning to his wife for the Jewish holidays. He had special agents that would keep an eye out all over Europe for teenagers with an aptitude for both scholarship and leadership, recruiting them and bringing them back to Slobodka. He attained unusual success, and his students subsequently reflected that he was a master of the human psyche and knew just which psychological buttons to press to give direction to his students' lives.
He would monitor the extra-curricular behavior of students judging their character faults and strengths. He was responsible for deciding which boys would share rooms together, weighing the strengths of one against the other. Some were chosen to be his personal assistants. He stressed the importance of outer appearance and the need for neatness and cleanliness. He did not want the image of the poor, tattered, down-trodden yeshiva bochur (yeshiva student) to be associated with the alumni of his institution. The rabbinical and Talmudical graduates of the Slobodka Yeshiva tried to live up to a higher code of dress and deportment, to the point of being accused of being dandies.
He would send teams of his trained prized pupils to places that needed a boost in religious observance and learning of Torah. His own son, Eliezer Yehudah (Lazer Yudel) eventually became the head of the far older Mir yeshiva, leading it all the way to Jerusalem where it is today the largest post-high school yeshiva in the world with thousands of students.
Rabbi Nosson Tzvi Finkel staged one of the most dramatic moves in the history of yeshivot. In the 1920s he decided to create a branch of his yeshiva in then Palestine , together with the dean Rabbi Moshe Mordechai Epstein, setting it up in Hebron and sending waves of hand-picked students there, culminating with his own permanent aliyah, going "up" ,to Palestine two years before his passing.
During his lifetime,he moulded many , such as the young Yitzchok Hutner ,who were eventually to become the heads (Roshei Yeshiva) of most of the so-called Lithuanian-style Yeshivot that were established in the United States and Israel during the 20th century, such as Rabbis Aaron Kotler , of Lakewood in New Jersey , Yaakov Kamenetzky of Torah Vodaath in Brooklyn , Elazar Shach in Bnei Brak Israel of Ponovezh , Yaakov Yitzchok Ruderman of Ner Israel in Baltimore , Dovid Leibowitz Chofetz Chaim in Queens , and Eliezer Finkel Mir in Jerusalem , as well as his own institution called Chevron which moved to Jerusalem following the massacre of Jews during the 1929 Hebron massacre in which some of the yeshiva students perished.