Guy Debelle will commence as RBA deputy governor for a five-year term on 18 September 2016.
Philip Lowe will begin his tenure as governor on the same day, replacing Glenn Stevens.
In announcing the appointment, Mr Morrison described Mr Debelle as an "economist of international standing" with a PhD in economics from Massachusetts Institute of Technology (MIT) and extensive experience at the RBA.
"Dr Debelle is currently the Assistant Governor (Financial Markets) at the RBA, a position he has held since March 2007. In that role, he has oversight of the Bank’s operations in the domestic and global financial markets, including the management of Australia’s foreign reserves," Mr Morrison said.