The move reunites Raiche with Toronto GM Jim Popp. Raiche served as Montreal’s co-ordinator of football administration when Popp was the Alouettes general manager.
"We are very excited to add Catherine to our front office team," Popp said in a statement. "She is talented and hard-working and will bring new ideas and fresh perspectives."
Raiche obtained her law degree from the University of Sherbrooke and was called to the Quebec Bar Association in 2012. She practised corporate and tax law for three years prior to joining the Alouettes.
The Argos also extended the contract of assistant GM Spencer Zimmerman. He originally joined Toronto in 2016 as its director of scouting and pro development before being promoted to assistant general manager in January 2017.