While his predecessor, Aaron ibn Sargado, was still in office, Nehemiah tried to have him removed; but the college insisted on retaining him, as he was in every respect superior to his opponent.
After Sargado's death, Nehemiah finally succeeded in seizing the office by a trick, although the majority of the college, headed by the ab bet din, R. Sherira, refused to recognize him, and he was supported by only a few members and some wealthy laymen.
Nothing is known of his scholarly attainments or of his activity as gaon. Nehemah died in 968, and was succeeded as gaon by Sherira Gaon.