Marshall was hired Friday as the team's defensive co-ordinator, while Sams will serve as offensive co-ordinator.
Marshall spent five years as a defensive coach with the Eskimos, from 2000 to 2004. He has 22 years experience as a defensive coach and helped guide Edmonton to a Grey Cup win in 2003.
"Greg is a veteran coach with a wealth of experience that will enable our young and talented defensive players to continue to grow," coach Kavis Reed said in a release.
Marshall, who played 10 seasons in the CFL as a defensive lineman, was head coach of the Saskatchewan Roughriders for the early part of the 2011 season, but was fired eight games in.
Sams is entering his 16th season as an offensive coach. He was the quarterbacks coach last season for the Hamilton Tiger-Cats.
His first stint in Edmonton was with the 1987 Grey Cup championship team as its special teams co-ordinator and defensive line coach.
"Doug has tremendous experience developing young quarterbacks," Reed said. "He is a proven signal caller with vast experience in the CFL and NCAA."