With the start of World War II and the Holocaust, Sarna expanded the scope of his activities: he was among the founders of the "Vaad Yeshivos", and was also active in the "Vaad Hatzalah". After the founding of the State of Israel, Sarna served as one of the leaders of the Chinuch Atzmai Torah School Network. Although he shunned direct political involvement, Rabbi Sarna had a strong affinity for Agudas Yisroel, and he was an active member of its Council of Torah Sages.