Schmalzried received his diploma (with a diploma thesis on the fluorescence of benzopyrene) from Theodor Förster at the University of Stuttgart and received his doctorate in 1958 at the Roentgen Institute of the University of Stuttgart with Richard Glocker (1890-1978) and was a postdoc with Carl Wagner at the Max Planck Institute for Biophysical Chemistry in Göttingen, a pioneer in solid state chemistry. He habilitated in 1966 at the Leibniz University Hannover on the topic of disorder in ternary ionic crystals. In 1966, he became a full professor at the Technical University of Clausthal and in 1975 at the Leibniz University Hannover. He was Courtesy Professor at Cornell University and Schottky Professor at Stanford University.
He wrote two textbooks on chemical reactions in solids, which were internationally standard works. He also dealt with thermodynamics of solids and electrochemistry. His group worked closely with Alan Lidiard's group in England.