Dehghan served as a commander in the Iranian Revolution Guards Corps (IRGC) and in its air force. He left his hometown for Tehran and joined the IRGC shortly after the Iranian revolution in 1979. His posts at the IRGC include commander of IRGC of Tehran (1980-1982), Isfahan, and Syria and Lebanon (1982-1983), and general manager of the IRGC’s Cooperatives Foundation (1996).
During the Iran-Iraq war, he was among leading and decision-making commanders of the IRGC along with Mohsen Rezaee, Rahim Safavi and Ali Shamkhani. In Syria and Lebanon he was the commander of the training corps of the IRGC. He was named the IRGC’s air force deputy commander in 1986 and became its commander in April 1990. His tenure lasted until 1992 and he was replaced by Mohammad Hossein Jalali in the post. Dehghan was named deputy chief of the IRGC Joint Staff in 1992. He later was promoted to the rank of brigadier general.