The Arab League's 22 member states have picked veteran Egyptian diplomat Ahmed Aboul-Gheit to head the body in a late-night session on Thursday.
Aboul-Gheit, who was the last foreign minister under former president Hosni Mubarak, was the only contender for the post of secratary-general.
The appointment came at a critical time for the Middle East, with Syria marking the fifth anniversary of its civil war, proxy wars between Saudi Arabia and Iran, and the battle against the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group raging across the region.
Aboul-Gheit, who has also served as Egypt's ambassador to the United Nations, had been widely expected to win approval from the league members.
It is a long-held protocol that Egypt, as host of the Arab League, traditionally nominates the chief. The league has been almost exclusively led by Egyptians.
Bahrain's Foreign Minister Khalid bin Ahmed Al Khalifa announced the decision after some last-minute wrangling over the appointment, saying that Aboul-Gheit would "serve a five-year term effective July 1" as secretary-general.
Diplomats told the AP news agency earlier on Thursday that Qatar and Sudan had opposed the choice of Aboul-Gheit, with Egypt and Saudi Arabia lobbying them to accept the choice.
Mohammed bin Abdulrahman Al-Thani, Qatar’s foreign minister, said its reservation "stems from reasons related to the character of the candidate," and not with Egypt itself.
The secretary-general can be elected by obtaining a minimum two-thirds majority of member states, but the group prefers to have unanimous agreement.
Divisions have weakened the Arab League since the 2011 uprisings that toppled three longtime autocratic rulers but also sparked armed conflicts.
Past league chairmen have included pan-Arab nationalists such as Amr Moussa and the outgoing head, Nabil Elaraby.
Aboul-Gheit appointment appears to mark a shift as he is known to be a pragmatic diplomat with strong enmity for Islamist factions such as the Muslim Brotherhood and Hamas, which rules the Gaza Strip.
|Aboul-Gheit [left] was the last foreign minister under Mubarak, who was toppled in Egypt's 2011 uprising [Reuters]