Milan Slimacek comes from the family of an organist, choirmaster and the Brno Conservatory teacher Josef Slimacek (1913-1973). He himself studied at the Conservatory, at first the organ playing in the class of Josef Pukl, later on he changed to study composition which he completed under the tutelage of Frantisek Suchy. In 1959-1963 he continued his composition studies at the Academy of Music and Dramatic Arts in Bratislava; there his teacher was Alexander Moyzes (in his memory he later composed his only programme work The Frescoes). Besides Moyzes at the Academy he was also influenced by Eugen Suchon, which reveals especially in the harmonic part of his musical language. After his graduation at the Bratislava Academy he returned to his native city of Brno where he first was a teacher at the Conservatory (1963 - 1971), then a director of music at the Czechoslovak Television (1971 - 1989) and finally a lecturer at the Faculty of Drama of the Janacek Academy of Music and Performing Arts (1989 - 1997). He used his singer training and performed both as a solo and choir singer; his practice of a piano player was also remarkable, particularly that of a pianist-improviser.

Thanks to his nature and classical education Slimacek belongs to the composers who start from the tradition and develop it in a creative way. As a composer he is closest to 20th century neoclassicism; in his compositions he applies the classical sense of balance and of clear and logical structure with a distinct main line and contrastive areas aside. He attains similar effect by his emphasis on the sound colour and on sensitive application of the human voice. Since the work on his Second String Quartet (1973) his characteristic principle has been that of permanent variation moving mostly between two areas of expression - lyrical and dramatical. In this very respect his work has some common points with expressionism, though without its typical pessimism and inclination to speculation.

As a composer Milan Slimacek left his mark on the chamber, choir, symphonic (overall almost eighty compositions) and scenic (over two hundred titles) areas.