Commenting on the appointment, Australian Ethical managing director Phil Vernon described Australian Catholic Super's $128 million investment as a "significant inflow".
"Increasingly, institutional investors are coming to understand that responsible investment should be a key part of their strategy," Mr Vernon said.
"This is a rapidly growing sector because clients are increasingly demanding that their investments align with their values, so it makes good business sense to offer quality responsible investment choices."
Australian Catholic Super chief executive Greg Cantor said many of his fund's members wanted to take a "strong stance" when it comes to responsible investing.
"We chose to appoint Australian Ethical to manage our responsible investment option as they are the clear leaders in this area, with a strong team and performance record," Mr Cantor said.
