Herries worked his way up in the Treasury and eventually became Secretary to the First Lord of the Treasury, Commissary-General to the Army, Paymaster of the Civil List, Secretary to the Treasury (1823–1827), Chancellor of the Exchequer in Lord Goderich's government (1827–1828), Master of the Mint under the Duke of Wellington (1828–1830), briefly President of the Board of Trade (1830), Secretary at War under Sir Robert Peel (1834–1835), and finally President of the Board of Control in Lord Derby's first government (1852).

During his tenure as Commissary-General, he used the help of Nathan Mayer Rothschild to transfer money to British and allied army troops on the continent, which was not an easy task during the Continental Blockade.

Staunchly protectionist, Herries was in repeated conflict with Disraeli who, despite championing protectionism barely six years before, was hurriedly disassociating himself and the party from that doctrine.

His son, Charles Herries, was appointed Chairman of the Board of Inland Revenue by Disraeli during the latter's second premiership in 1877.

Herries survived her by over thirty years and died at St Julians, near Sevenoaks, Kent, in April 1855, aged 76.