He played "a major role in establishing the study of coinage as an essential technique of Indian historical research", for which he received numerous awards and honours, and was the first Honorary Fellow of the Numismatic Society of India.
In 1902 he was selected for the Indian Civil Service, and came to specialise in "Settlement" work - the periodic reassessments of land revenue - and through this work came to understand the historical interest of the coin finds that were being made in the Punjab at the time.
To bring together scattered research, in 1910 he and six others took part in a meeting at Allahabad at which was founded the Numismatic Society of India.
He married Margaret Elizabeth, widow of James Hector Barnes, I.C.S., and daughter of Col. F.T.
Whitehead wrote numerous books, articles and reviews, of which the following is a selection: