After a two-year work as a lecturer in Frankfurt, Kohlrausch was appointed a professor of physics at the University of Göttingen (1866–70).
During 1870 Kohlrausch became a professor at ETH Zurich in Switzerland. One year later, he moved to the Darmstadt University of Technology in Germany.
In 1875, he responded to an offer from the University of Würzburg in southern Germany, where he subsequently conducted his experiments in quantity determination and the conductivity of electrolytes. From 1888 he researched and taught at Strasbourg University.
He refused a professorship at the Humboldt University in Berlin in 1894, but from 1900 he was also a professor there. He was elected an International Honorary Member of the American Academy of Arts and Sciences in 1900 and an International Member of the United States National Academy of Sciences in 1901. He was elected a member of the Royal Swedish Academy of Sciences during 1902. He was elected to the American Philosophical Society in 1909.