In 1588 he became shah, by revolting against his father, Mohammad Mioza of Safavid. Because of the weakness of his army, he made an unfavorable peace with the Ottomans in 1590 and chose Isfahan in 1598 as his capital. A year later, the English Sir Robert Sherley directed a major army reform. With his new army, the Uzbeks (1597) and the Turks (1603) were defeated, forcing them to give back the territory they had seized, including Baghdad. He also expelled the Portuguese traders who had seized the island of Hormoz in the Persian Gulf. Shah Abbas' reign, with its military successes, efficient administrative system, raised Iran to the status of a great power. Abbas was a great diplomat, tolerable to his Christian subjects in Armenia and sending Sherley to Italy, Spain and England in order to create a pact against the Turkish.
Trade with the west and industry grew. Esfahan became the center of Safavid architectural achievement, with the mosques Masjid i Shah and the Masjid i Sheykh Lotfollah; and other monuments like the Ali Qapu, the Chehel Sotoun, and the Meydan-i Shah.
Afraid of a coup by his family (like he had done to his father), he locked them up in palaces in order to keep them without knowledge of the outside world. This resulted in weak successors. It is said that he killed his eldest son and left his throne to his grandson.