Rabbi Nosson Tzvi Finkel, the Alter of Slabodka, was born in 1849 in Rasseyn (Raseiniai), Lithuania, the son of Moshe and Miriam. Orphaned very young, he grew up in his uncle's home in Vilna. He married Gittel Wolpert, granddaughter of Rabbi Eliezer Gutman, rabbi of Kelm. On a visit to his hometown, the rabbi of Rasseyn, Rabbi Alexander Moshe Lapidot, who was close to the Mussar movement, was struck by the young man and gave him a letter, whose contents he did not know, for Rabbi Simcha Zissel Ziv, the Alter of Kelm, asking him to keep an eye on him. He thus became a student of the Alter of Kelm, and his influence on those around him soon became known.

He was one of the great masters of the Mussar movement and founder of the Knesset Yisrael yeshiva of Slabodka, near Kovno, the mother of the "Slabodka school". His teaching stressed the greatness of man (gadlut ha'adam), created in the image of God: the student had to become aware of his worth and responsibility. A very private man, he watched over each of his students personally. His yeshiva produced a great many Torah leaders who went on to head yeshivot around the world, notably in the United States and Israel.

In 1924 he moved part of the yeshiva to Hebron in the Land of Israel, where he settled; after the massacre of 1929, two years after his death, the yeshiva relocated to Jerusalem. He passed away on 29 Shevat 5687 (1927).