The 51-year-old coach replaced Spanish coach Manel Benavente, who was appointed as the team’s interim coach on Monday.
Mansourian was without a team since parting company with Sanat Naft last year.
Foolad, under leadership of Javad Nekounam, qualified for quarterfinals round of 2022 AFC Champions League, where it lost to Al Hilal 1-0.
The team sits ninth in the Iran league table, 18 points behind leader Sepahan.