 Hesayne was the bishop of Viedma for 20 years, until 28 June 1995, when he resigned.He ruled his episcopal see during the dictatorial regime of the National Reorganization Process (1976–1983), and was among the very few members of the Argentine Catholic hierarchy to openly criticize its human rights abuses and crimes, such as the murder (masqueraded as a road accident) of bishop Enrique Angelelli by a military task force in 1976.Hesayne died on 1 December 2019 at the age of 96.