His father was Benjamin Edwardes, rector of Frodesley, and his grandfather Sir John Edwardes, baronet, eighth holder of a title conferred on one of his ancestors by Charles I in 1644. He attended boarding school and subsequently went on to study at King's College London.
Through the influence of his uncle, Sir Henry Edwardes, he was nominated on arrival in India, and at the beginning of 1841, he was posted as an ensign in the 1st Bengal Fusiliers. He remained with this regiment about five years, during which time he mastered the lessons of his profession, and obtained a good knowledge of Hindustani from the frontier peoples during the war. So effective was his procedure for the safety of the border that he was able to raise a large force in the Punjab and send it to co-operate in the siege and capture of Delhi.
In 1859 Edwardes once more went to England, his health so greatly impaired by the continual strain of arduous work that it was doubtful whether he could ever return to India. During his stay he was created KCB, with the rank of brevet colonel; and the degree of LL.D. was conferred upon him by the University of Cambridge.
Early in 1862 he again sailed for India, and was appointed commissioner of Timballa and agent for the Cis-Sutlej states. He had been offered the governorship of the Punjab, but on the ground of failing health had declined it. In February 1865 he was compelled to finally resign his post and return to England. A second good service pension was at once conferred on him; in May 1866 he was created Knight Commander of the Star of India; and early in 1868 was promoted major-general in the British Indian Army.
He had been for some time engaged on a life of Sir Henry Lawrence, and high expectations were formed of the work; but he did not live to complete it, and after his death it was put into the hands of Herman Merivale. He died in London on 23 December 1868. Great in council and great in war, he was singularly beloved by his friends, generous and unselfish to a high degree, and a man of deep religious convictions.
See Memorials of the Life and Letters of Sir Herbert Benjamin Edwardes, by his wife (2 vols., London, 1886); T. H. E. Holmes, Four Soldiers (London, 1889); John Ruskin, Bibl. pastorum, iv. A Knight's Faith (1885), passages from the life of Edwardes.