Engman, who 1968-73 was an official at the Finnish national archives in Helsinki, published 1983 a much noticed dissertation about S:t Petersburg and Finland. He was appointed professor 1985 in general history at Åbo Akademi .
Engman has in his research foremost studied the Finnish-Russian relations and the European empires. He has also studied constitutional issues and the administration. His contribution as subeditor for Historisk Tidskrift för Finland 1971-82 and the journals editor in chief 1982-2000 is considered as great.