Hammer participates in the Zionist youth group Bnei Akiva and serves in the Israel Defense Forces’ Armored Corps with the Nahal program, which combines military service with the creation of agricultural settlements. He studies Judaism and the Bible at Bar-Ilan University, where he chairs the student union and is active in the leadership of the Israeli Students Association and the World Union of Jewish Students. He works as a teacher after graduation.
Hammer is first elected to the Knesset in 1969 and is re-elected seven consecutive times before dying of cancer in 1998. He is a member of the Foreign Affairs and Defense Committee for most of his time in the Knesset and serves on the Constitution, Law and Justice Committee, the House Committee, the Internal Affairs Committee, and the Education and Culture Committee. He also is part of an ad hoc panel formed in response to Kurt Waldheim’s election as Austria’s president in 1986 despite allegations of Nazi war crimes against him.
Over the years Hammer serves as welfare minister, education and culture minister (five times), and religious affairs minister (four times). He also serves as the chairman of the National Religious Party.