He became a pupil in the gymnasium at Stuttgart at a comparatively late age, and in 1848 he entered the Eberhard Karls University of Tübingen, where he studied oriental languages, especially Sanskrit.
Having returned to Stuttgart in 1866, he was called to Munich as professor of Sanskrit and comparative philology in 1868.
It was Dr. Haug who originally outlined the structure of the popular Sanskrit introductory books by Bhandarkar which was used throughout India in the early 20th century.
The result of his researches in Poona was the volume Essays on the sacred language, writings and religion of the Parsees (Bombay, 1862), of which a new edition, by E. W. West, greatly enriched from the posthumous papers of the author, appeared in 1878.
Haug published a number of other works of considerable importance to the student of the literatures of ancient India and Persia.