Rabbi Ari Katz joined the Hesder program in Kerem B'Yavneh in 1985. In this context, he served in the army's artillery corps and was later appointed a military chaplain. He learned in the Yeshiva for nine years, completing his semicha through the Chief Rabbinate of Israel and earning a teaching diploma from the teachers' seminary in Kerem B'Yavneh. After serving as a popular madrich for 5 years, in 1994 Rabbi Katz went with his family on shelichut to Memphis, Tennessee, serving as a rebbe in the Feinstone Yeshiva of the South for five years. Upon his return to KBY in 1999, Rabbi Katz was appointed assistant Mashgiach Ruchani and delivered a daily bekiyut shiur for the overseas students.

True to his love of Eretz Yisrael and Am Yisrael, in 2004 Rabbi Katz moved with his wife and five children to Gush Katif, becoming a Rosh Yeshiva at a local boys' high school. Rabbi Katz's special ruach added much strength to the residents of Gush Katif during the trying period leading up to the Disengagement. After the Disengagement, Rabbi Katz returned with his family to KBY; shortly thereafter, he was chosen to replace the long-standing Director of the Yeshiva, Mr. Eli Klein. Even with his busy schedule, Rabbi Katz makes the time to get to know all of the overseas students in Yeshiva.