Hillert graduated from Chalmers University of Technology in 1947 with a major in chemical engineering. After military service he joined the Swedish Institute for Metals Research in 1948. He investigated his options for postgraduate studies related to his new area, and took additional physics courses at KTH. In 1953 he moved to the United States for postgraduate studies at the Massachusetts Institute of Technology, where he earned an Sc.D. in 1956, after which he returned to Sweden. He was made a professor at KTH in 1961.
In 1973, he was elected a member of the Royal Swedish Academy of Engineering Sciences, and in 1982 a member of the Royal Swedish Academy of Sciences. In 1979 he was awarded an honorary doctorate by the Chalmers University of Technology.
- Thermodynamics and Phase Transformations - The Selected works of Mats Hillert. (2006) s. iii. A short presentation of Mats Hillert
- Chalmers: Hedersdoktorer: Mats Hillert, accessed on July 9, 2009 (Swedish)