In the early 1990s Jachter served as an associate rabbi in Congregation Beth Judah, Brooklyn, while studying for his rabbinical ordination. In 1993 he joined the rabbinical court of Elizabeth, New Jersey as a dayan and get administrator. He is also certified as a get administrator by the Chief Rabbinate of Israel and given a letter of certification from Rav Ovadia Yosef. By 2008, Jachter estimated he had overseen more than 2,000 Jewish divorces. He chairs the Agunah Prevention and Resolution Committee of the Rabbinical Council of America. In 2015 Jachter testified in a U.S. district court case involving an attack on a Jewish man who had refused to give his wife a get. He is a strong proponent of civil prenuptial agreements, which avoid the issues created if the husband refuses to give a get. Jachter requires every couple he marries to sign the RCAprenuptial agreement. He and his wife, Malca, signed the RCA prenuptial agreement before their own wedding. Jachter is the Rabbi of Sha'arei Orah, the Sephardic Congregation of Teaneck. He is also a community eruv designer who has advised dozens of American Jewish communities in the construction and maintenance of their eruvs. Jachter joined the faculty of the Torah Academy of Bergen County, a yeshiva high school, in 1995. In tandem with his teaching duties, he serves as faculty advisor for the school's weekly Torah publication, Kol Torah, to which he also contributes articles on halakha topics. These articles formed the basis for his books Gray Matter, Gray Matter 2, Gray Matter 3, Gray Matter 4, and Reason to Believe: Rational Explanations of Orthodox Jewish Faith. Jachter also established and serves as director of the TABC alumni foundation. Jachter has also written 2 books on Tanakh, , written with his son, Binyamin, and . These books discuss questions and lessons to be learned from the books of Jonah and Kings, respectively.
Articles and lectures
Jachter writes on a wide variety of contemporary topics in Jewish law, among them the use of electricity on Shabbat, infertility, and owning pets. His many columns and lectures on topics in Halakha, Aggadah, and Tanakh are available online at www.koltorah.org and www.yutorah.org. Jachter's Gray Matter book series discusses contemporary halakhic issues that have arisen during his career with the Beth din and RCA. Gray Matter, for example, discusses the aspects of forcing a man to give a get, while Gray Matter 3 presents the issue of mamzerim. Reason to Believe discusses both the Modern Orthodox and Haredi viewpoints on conflicts between Torah and scientific knowledge.
Personal life
Jachter married Malca Tokayer in 1995. They have five children and reside in Teaneck, New Jersey.