Augustus Hardenbergh entered Rutgers College in 1844, but an infliction of blindness upon his father compelled him to leave before his course was finished to assist in his father's law office. In 1851 the college conferred upon him the degree of Bachelor of arts in recognition of the good work he had accomplished during his brief collegiate career. In 1846 he entered a mercantile house in New York, becoming a resident of Jersey City. In 1852 he became connected with the Hudson County National Bank, was appointed its Cashier in 1858, and in 1878 was elected President, a position he held until his death.

Mr. Hardenbergh early became interested in politics. He was elected to the State Legislature as a Democrat when only twenty-three years of age (1853). During the session of 1854 he acquired a favorable State reputation by securing the passage of the general banking act and by opposing the Camden and Amboy Railroad monopoly. In 1857 he was elected a member of the Jersey City Common Council, as Alderman, and was re-elected thereafter until 1863, serving a part of the time as President of that body and as Chairman of the War Committee. In 1868 he was appointed State Director of Railroads.

Having removed to his Bergen County home, he was elected a delegate from the Fourth Congressional District to the Democratic National Convention at Baltimore, which nominated Horace Greeley for President, and in the same year was chosen President of the Northern Railroad Company of New Jersey. In the fall of 1872 he removed to Jersey City and in 1876 was elected to the Forty-fourth Congress, to which he was re-elected in 1878. In 1880 he consented to accept a re-nomination to Congress to save his party from threatened defeat and was again elected by over 5,000 majority. During this period he succeeded in making Jersey City a port of entry. In 1883 he was appointed a member of the Board of Finance and Taxation and his services were marked by saving the credit of the city during the financial depression of that year. In 1884 he was appointed by Governor Abbett as a Trustee of the State Reform School. He served as a member of the Board of Finance until 1889, when the board went out of office. The unique place which Mr. Hardenbergh held in the affections of the community is shown by the following newspaper characterization at the time of his death:

Mr. Hardenbergh was one of the most widely known men in this section of the country. He made a record in Congress that brought him into close and intimate relations with the chief men of New York and Pennsylvania. Of course every man of any account in New Jersey was his personal friend. He has been so active in Hudson County, in public and private ways, that his name was a household word from Bull's Ferry to Bergen Point, and his death comes to almost every man, woman, and child here with the sting almost of a personal bereavement. Without a single exception he was the most popular man in the county, and his individual strength has more than once helped to save his party from disaster in times of threatened peril.

His chief characteristic was his sterling integrity. All of his life has been spent under the public eye. He has been commissioned by the people to the discharge of countless trusts. Never a man carried himself so straight as he. Suspicion did not dare to blow even a breath at him. And he had the personal confidence of every man as thoroughly as he had the confidence of the masses as an aggregate.

If a little estate was to be administered, Gus Hardenbergh – as everybody felt at liberty to call him, so close was he to men everywhere – was chosen to administer it. If a dispute was to be decided he was often made the final arbiter.

Add to the influence such a reputation gave him his other qualities of mind and disposition, and wonder ceases as to the reasons for his personal strength. An entertaining companion, a fluent and often eloquent talker, a thinker of great mental force, a friend whose purse and services were always at the command of those who needed them, and a man of fearless honesty – that was Mr. Hardenbergh as this community knew him.