In 1959 he graduated from the Faculty of Mathematics and Physics at Charles University in Prague, and then worked at the Czech Technical University in Prague, the University of Žilina, Faculty of Mathematics, Physics and Informatics at the Comenius University in Bratislava, and since 1991 he has been lecturing at the Faculty of Education at Charles University in Prague. For a number of years, he taught mathematics experimentally at elementary school. He spent a year as a guest professor at the Concordia University in Montreal (Canada) and six months at the Central Michigan University in the USA. In the 1990’s, he was deputy minister of education in Slovakia, and since 1991 he has been a professor at the University of Education at Charles University in Prague.
Here, his research team elaborated a theory of generic models and conceived the “schema-oriented” education theory, also known as the teaching theory focussed on building schemata. From 2005 to 2011 this team compiled a set of mathematics textbooks for 1st level elementary schools. In 2013, it founded the public welfare society H-mat, o.p.s., which serves to develop and disseminate the work started by him and his father.
Prof. Hejný is the author or co-author of 16 mathematical publications and more than 270 publications in mathematical didactics, including 13 very frequently cited books. He has lectured at 13 foreign universities and more than 30 international conferences, has been a solver or co-solver in 7 domestic and 4 international grant projects, and acts as a member of the editing board for the Educational Studies in Mathematics magazine and the editing board of the Kluwer publishing house for the Mathematics Teacher Education series.
His main scientific results in the field of mathematical didactics include:
His method for teaching mathematics is based on the theory of generic models and leads pupils to create generic models and schemata. It is based on the findings of his father Vít Hejný and his own experience as a mathematics teacher at elementary school in Bratislava. In essence, the teacher assigns interesting problems to the pupils and lets them solve them collectively. The pupils must create their own “generic models” for solving the problems, and they must enjoy the activity. Milan Hejný and the team from the Charles University in Prague, Faculty of Education have compiled a number of mathematics textbooks for first level elementary schools, including teacher handbooks. He is an honorary member of the Union of Czech Mathematicians and Physicists, an honorary member of the Slovak Union of Mathematicians and Physicists, and holder of the golden plaque of the Faculty of Mathematics, Physics and Informatics of the Comenius University in Bratislava. In 2010 he was awarded the 1st degree Medal of the Ministry of Education, Youth and Sports for extensive excellent educational activity. In 2012 he received the “MathProf ONE” award within the “Czech 100 Best” project. In 2013 he was given a special award within the “Making Math Fun” project.