Shamkhani first served as the commander of the Islamic Revolution Guards Corps (IRGC) Navy. Later he commanded the Iranian Army's naval force in addition to the IRGC Navy.
He then became Iran's defense minister from August 1997 to August 2005 in the government of President Mohammad Khatami. When Ahmadinejad ascended to power in 2005 Shamkhani was replaced with Mostafa Mohammad Najjar in the post. In the 2001 presidential election, Shamkhani ran for office.
He is the director of the Iranian Armed Forces' Center for Strategic Studies and a military advisor to Supreme Leader of the Islamic Revolution Ayatollah Ayatollah Ali Khamenei.
Shamkhani will replace Saeed Jalili who served as SNSC Secretary during President Mahmoud Ahmadinejad's tenure and represented Iran in nuclear talks with the world powers. The SNSC is, of course, not anymore in charge of the talks after President Rouhani in a decree last week shifted the leading role in the talks with the Group 5+1 (the five permanent UN Security Council members plus Germany) to the Foreign Ministry.
Yet, Iranian Foreign Ministry Spokeswoman Marziyeh Afkham told FNA on Thursday that coordination for the Iran-powers talks will still be done by the SNSC, although the negotiations will be carried out by the foreign ministry.