He was the eldest son of General Thomas McCall Cadwalader (1795–1873) and the former Maria Charlotte Gouverneur (1801–1867).

In 1878, he became a name partner of Cadwalader, Wickersham & Taft, the oldest continuously operating law firm in the United States, which still carries his name.

"[2] Cadwalader was at one time president of the New York City Bar Association, but his most prominent connection in the minds of the public was with the New York Public Library, of which he was elected the second president, as the successor of John Bigelow.

For many years before his election to this office, he had been a member of the board of trustees and of the executive committee of the library.

He worked out the plans for combining the Astor, Lenox, and Tilden foundations into one great, central library, and was instrumental in the material carrying out of this conception.

In his will, he left to "each of the clerks in the office of Strong & Cadwalader," who had been working for the firm for five years prior to his death, "a sum of money equal to six times their monthly wage.