He studied medicine in Munich and Vienna, and in 1847 was habilitated as a lecturer of pathological anatomy and microscopy at the University of Munich. In 1850 he was chosen as an associate professor, and from 1854 served as prosector at the university general hospital. In 1859 he was appointed professor of general pathology and pathological anatomy in Munich, where in 1875 he became director of the pathological institute. Two of his better known assistants were Ernst Schweninger (1850-1924) and Wilhelm Heinrich Erb (1840-1921).
With Max Pettenkofer (1818-1901), Carl von Voit (1831-1908) and Ludwig Adolph Timotheus Radlkofer (1829-1927), he published the biological journal Zeitschrift für Biologie. His best written effort was the 1872 Lungenentzündung, Tuberkulose und Schwindsucht, a book that was later translated into English as Inflammation of the lungs: tuberculosis and consumption (1874).
Buhl is remembered for his work with infectious diseases, in particular, pioneer research of miliary tuberculosis. With Austrian pathologist Franz Dittrich (1815-1859) is obtained the "Buhl-Dittrich law", a supposition that states that "In every case of acute miliary tuberculosis, there exists at least one old focus of causation in the body".
His name is associated with "Buhl's disease", a rare disorder of newborns that he first described in 1861. The disease is defined as an acute parenchymatous fatty degeneration of the liver, kidney, or heart, combined with hemorrhages into the various organs.