After a brief attempt at reviving the Jewish community in Newport, Rhode Island, he accepted an appointment as the first rabbi of Congregation Nidche Israel in Baltimore.
Rice usually delivered his sermons in German, later occasionally in English, and insisted on retaining all the traditional piyyutim in the prayers.
[1] Rice was known throughout the United States and Germany as a learned Talmudist, and as the only ordained rabbi in the country he was asked to decide many questions of halacha.
He was an uncompromising opponent of Reform, a frequent writer in Isaac Leeser's The Occident, and advocated establishing an American beth din to strengthen Jewish observance.
In 1849, finding it impossible to resist the demand for reforms at Nidche Israel, he resigned his position, founded his own synagogue which was strictly Orthodox; to support himself he opened a dry goods store, and then a grocery.