Heikel was born in 1861 in Nykarleby, Finland to pastor August Heikel and Aurora Emilia née von Knorring and had seven siblings. Heikel became associate professor (docent) of Classical Philology at the University of Helsinki in 1885 and was professor of Greek Literature between 1888 and 1926. He was rector of the university from 1907–1911 and 1920–1922.[4]
In his extensive writings he dealt mainly with ancient subjects. He developed a particular interest in early Christian scholar Eusebius of Caesarea.[4] As emeritus, he devoted himself to translation work as well as translating Eusebius' Church History into Swedish and Finnish.[5]
^L. Arvi P. Poijärvi, Ilmari Havu, Mauno Jääskeläinen (eds.): Kuka kukin on (Aikalaiskirja). Henkilötietoja nykypolven suomalaisista 1950, p. 164. Helsinki: Kustannusosakeyhtiö Otava, 1949. (in Finnish)