Rabbi Avraham Shmuel Binyamin Sofer, the Ktav Sofer, was born in Pressburg on 1 Adar I 5575 (1815), the son of the Chatam Sofer, rabbi of Pressburg, and of Sarah, daughter of Rabbi Akiva Eiger. His birth, after long childless years, was greeted with immense joy. At six he fell so gravely ill that the Chevra Kadisha had already made the final preparations; his father prayed for him and added the name Avraham. He recovered and lived another fifty years. He married Chava Leah, daughter of Rabbi Yitzchak Weiss of Gorlice.

When his father died on 25 Tishrei 5600 (1839), he succeeded him, despite his youth, as rabbi of Pressburg and head of its great yeshiva, which he led for more than thirty years and which flourished under him. Regarded as one of the giants of his generation, he was a leader of Hungarian Orthodoxy at the time of the split with the Neologs, and carried on his father's fight for tradition against Reform, with great gentleness.

His works, collected as Ktav Sofer, comprise responsa and commentaries on the Torah and the Talmud. He passed away on 19 Tevet 5632 (1871) and rests in Bratislava, near his father.