Greeley's management, among the most noted of which were the cases of the notorious Count Johannes, and of Dewitt C. Littlejohn, at that time Speaker of the Assembly, in both of which cases Mr. Williams was successful. He was also associated with Charles O'Conor in several important suits. For a time he was partner of Francis B. Cutting; but his mind was of a cast which rendered him impatient of partnerships, and he much preferred to be alone, assisted only by clerks. He did not confine himself wholly to the practice of his profession, but took an active part in the political struggles of 1856, when he made speeches in favor of his old friend, Mr. Fillmore, and in 1860, when he spoke for Lincoln. During the war he took a part in the exciting controversies of that period, sharing in the dangers which surrounded Mr. Greeley and those who acted with him.

Mr. Williams did not confine himself to those questions of public interest which pertained more especially to America. In 1857 he visited Europe, where he interested himself in the ballot question which then agitated England, making speeches in its favor both in England and Wales. While abroad he visited the principal capitals of Europe, enjoying exceptional facilities for meeting prominent men, because of Mr. Fillmore's letters of introduction. In Paris, in London and at Oxford University he received marked attention from men distinguished in scholarship, politics and law, by whom he was sought, for his brilliant conversational powers. While in Paris he was thrown into the society of Charles Sumner, between whom and Mr. Williams a friendship was formed, which survived with unabated warmth for many years.