Popp spent over two decades as General Manager of the Montreal Alouettes including several stints as Head Coach.

Popp served as General Manager for two years for Baltimore Stallions, and the Director of Player Personnel for the Saskatchewan Roughriders.

As a CFL general manager, three separate franchises under Popp have won five Grey Cup championship wins out of 11 appearances.

The Alouettes had the second highest win percentage of any sport (#1 New England Patriots) during a decade run that saw the team appear in 8 Grey Cups over 11 seasons.

Due to his knee injury, Popp worked for Perles at Michigan State in 1986 as a graduate assistant coach, under Saban and Baggett's tutelage.

In 1991, he served as the wide receivers, special teams coordinator, and strength and conditioning coach for the Raleigh-Durham Skyhawks of the World League of American Football, led by Roman Gabriel.

[1] Popp was the Saskatchewan Roughriders' Director of Player Personnel and Wide Receivers coach under Don Matthews in 1992–1993.

After the National Football League added the Baltimore Ravens, Stallions owner Jim Speros decided to relocate his team to Montreal as the second incarnation of the Montreal Alouettes, and Popp was named Vice President, General Manager, Director of Football Operations, and Director of Player Personnel in January 1996.

Popp hired Corey Chamblin, the defensive coordinator during the Argos' 2017 championship season to be the head coach in for the next year.

During the 2001 season, Popp took over the team after owner Robert C. Wetenhall fired Rod Rust in the midst of a long losing streak.

On October 4, 2006, following the resignation of Don Matthews for health reasons, Popp again took over as head coach and led the Alouettes to an appearance in the 2006 Grey Cup.

[7] Popp continued as the head coach for part of the 2016 CFL season before stepping back as strictly the General Manager.