Freundlich was born at Charlottenburg, now a district of Berlin, Germany. He studied physical chemistry at Munich and at Leipzig where he became assistant to Wilhelm Ostwald. From 1911 to 1917 he was professor at the Institute of Technology in Brunswick. He was professor at the Kaiser Wilhelm Institute, Berlin-Dahlem, from 1917 to 1934 when he left Germany because of the Nazi regime. He traveled first to Britain and worked at University College, London, and from 1938 to his death was professor of colloid chemistry at the University of Minnesota.

Freundlich's life work was in colloid chemistry. He showed how colloid stability was changed by the addition of electrolytes and he is well known for the Freundlich adsorption isotherm, a theoretical formula for the amount of adsorption on a surface at constant temperature.