"Maybe 40 years ago, some of Iran's actions were out of excitement and emotional," he told US media on Monday, adding that Iran will respond in a "mature" way.
Tehran's response is not expected to be like the hours-long attack seen in April, he added.
Shafieian said the assassination of Haniyeh "was an intelligence-based mission," adding that "Iran's response will be of a similar nature and at a similar level."
Iran said that its response would be limited to avoid escalating the conflict, a member of the Iraqi parliament with ties to Iranian-backed militias in the country told the newspaper.
"We were told [by Iran] that it's going to be a limited response," he said, adding that Tehran "doesn't want to expand the war."
Meanwhile, a Lebanese with ties to the Hezbollah movement told the newspaper that Iran was worried Israel and the US could strike its nuclear program to "essentially neutralize Iran's nuclear deterrence."
On July 31, Hamas said that an Israeli attack had killed Haniyeh in his residence in Tehran, where he arrived to attend the inauguration of Iran's new president. The movement held Israel and the US responsible for Haniyeh's death and said the attack would not go unanswered.