In 1950 Blackman was appointed music director at Regina Central Collegiate Institute, later becoming supervisor of music for the Regina high schools in 1961. In 1954–1955 he conducted the Saskatchewan Golden Jubilee Chorus and in 1959 his musical, "Prairie Pastel" (for which his wife Elisabeth Blackman wrote the libretto), was presented for the Regina school's 50th anniversary. In 1962 he founded the Regina Inter-Collegiate Choir and Orchestra, ensembles with which he notably led performances at Expo 67 and on tours to Vancouver, Calgary, London (1972), and Minneapolis and St. Paul (1974). From 1963 to 1980 he was coordinator of fine arts for the Regina Board of Education. He also taught courses in music education at the University of Regina and the University of Saskatchewan and worked periodically in the summers as the orchestra conductor for the Saskatchewan Summer School of the Arts.