Engman worked at the Finnish national archives in Helsinki from 1968 to 1973. He was appointed professor 1985 in general history at Åbo Akademi. His works focused in Finnish–Russian relations and the European empires.
He was known as a subeditor for Historisk Tidskrift för Finland from 1971 to 1982 and the journals editor in chief 1982 to 2000.
Engman died on 19 March 2020 in Helsinki at the age of 74.