In May 1881, Nissen opened the jewelry shop "Schilling and Nissen" with the Hamburg diamond setter Fred Schilling. The company was burdened with debts, but had a quick upswing. In 1885 he founded his own firm, Ludwig Nissen &amp; Co. He moved his business to the most prestigious street in New York, Fifth Avenue. He became involved in the New York jeweler's trade union, and became its treasurer in 1891. In 1895 he rose to the rank of Vice President and, eventually, President. Other honorary offices brought him further respect: in 1897, he became Commissioner for the City of Brooklyn for the Atlanta Exhibition, in 1901 for the Pan-American Exposition in Buffalo, in 1898 he was elected President of the Manufacturers’ Association of New York and in 1900 he was appointed Treasurer of the New York State Commission for the World's Fair in Paris.