[1] Ziv married Sara Leah, the daughter of Mordechai of Vidzh, a small town near Kelm.
Following his marriage he travelled to Kovno, where he studied under his foremost mentor, Yisrael Salanter, the founder of the Musar movement, at the Nevyozer Kloiz.
During this time, Salanter sent Ziv to Zhagory, to strengthen the Beis HaMusar (Musar study house), which had been established there.
At the time, Kalman Zev Wissotzky (who later became famous as a tea magnate) was another of Salanter’s students living in Zhagory.
In 1881, he returned to Kelm, leaving his son, Nochum Zev Ziv to run the Talmud Torah in Grobin.
Young men from Kelm and the surrounding areas flocked to study under Ziv and the town once again became a center of Musar.
In that year, Ziv's health took a turn for the worse and his doctors warned him that there was real danger to his life if he continued making the effort that the running of the yeshiva in Grobin required.
With the closure of the Grobin Talmud Torah, the focus of his work shifted back to Kelm, which now regained its former prominence.
A number of his students settled in Palestine in 1892, opening the "Beis HaMusar" in Jerusalem, under Ziv’s auspices and with his support.
There are numerous anecdotes that illustrated the extent that this reached, among them are: Ziv explained that a person can only progress in life and perceive God by clearing his mind of confusion and haphazard thinking.
Ziv would study for twelve solid, successive hours each day no matter the time of year.
[5][1] His foremost student was Yeruchom Levovitz the Mashgiach of Mir, who wrote all of his texts into Chochmah Umussar, due to the fact that no one else was able to put it out.
His other students included many of the musar greats of the next generation: Nosson Tzvi Finkel of Slabodka, Aharon Bakst, Reuven Dov Dessler (whose son Eliyahu Eliezer Dessler authored the classic Michtav M'Eliyahu), Nachum Ze'ev Ziv, and Zvi Hirsch Braude.
Among these are Yosef Leib Bloch, the rabbi and Rosh Yeshiva of Telz, Yosef Yoizel Horowitz of Novhardok, Elya Lopian of the Knesses Chizkiyahu Yeshiva in Israel, and Chaim Yitzchak Bloch Hacohen, the chief rabbi of Bausk and Plunge.
Additional letters, as well as transcriptions of his words by his disciples, appear in a series of volumes under the title Kitvei Ha-Sabba Mi-Kelm.