Porter joined the Steelers staff after receiving his first coaching experience at his alma mater last season as a student assistant on Colorado State coach Jim McElwain's staff while taking classes to complete his degree.
Porter worked with the Rams' pass rushers, including linebacker Shaquil Barrett, who posted 12 sacks.
Steelers coach Mike Tomlin said: ''We are excited about having Joey back with the Steelers' family. Joey spent a number of years with Pittsburgh as a player, and now he's back to assist the coaching staff. We look forward to his efforts and contributions.''
Porter played 13 NFL seasons with Pittsburgh, Miami and Arizona and was a four-time All-Pro.
AP NFL website: www.pro32.ap.org