[2] Newbold was educated at schools in Poughkeepsie (including the Fen Stanton Vicarage)[3] and Trinity Hall, University of Cambridge, receiving a B.A.

[3] He then became a lawyer,[4] studying in the office of Sanford, Robinson & Woodruff, eventually graduating from Columbia Law School in 1874.

[3] After retiring from the Senate, Newbold served as the president of the New York State Department of Health in the 1880s and 1890s, succeeding Erastus Brooks.

[18][19] Together, they were the parents of:[16] In 1916, he hired McKim, Mead & White to build a new residence for his family at 15 East 79th Street (which today is the Rudolf Steiner School).

The architects tore down two identical brownstones and built an Italian Renaissance style palazzo with an arched double-door entrance.

After his death, his estate was divided equally among his three children with his eldest daughter Mary inheriting their New York City residence and Bellefield in Hyde Park.