Sam is the first openly gay player to be drafted by an NFL team. The St. Louis Rams selected the pass rusher in the seventh round in 2014. He appeared in four pre-season games before the team released him, then had a short stint on the Dallas Cowboys' practice squad that ended in October without his playing a regular-season down in the NFL.
Montreal announced last Friday that it had signed the 25-year-old Texan to a two-year deal, and he'll report to training camp when it begins Wednesday.
"I'm so excited to get back on the football field and get back to work," Sam said.
Alouettes general manager Jim Popp said the "trailblazing athlete," who was a U.S. collegiate star at Missouri, can make an impact in the pros.
"We think he has a chance to be an outstanding pass rusher in the CFL," Popp said.
Sam brushed off a reporter's comparison between himself and Jackie Robinson, who played for a minor-league team in Montreal before breaking the colour barrier in Major League Baseball.
"I'm just here to play football," Sam said. "I'm not here to try to do anything historic."
He did, though, have a message for Montreal's LGBT community.
"If you're afraid of what your family and friends may think ... come to me. I'll be your family."