An appeals court in the former rebel stronghold of Misurata found Ibrahim, along with nine others, guilty of the murder of a family in Sirte, the birthplace of former leader Moammar Gadhafi.
Ibrahim was the minister of education in Gadhafi's government. The Libya Herald reported Wednesday the court added charges of incitement to commit murder and terrorizing civilians during civil war.
The crimes were committed before Sirte was liberated by anti-Gadhafi forces. Gadhafi died after falling into rebel hands near the city during the final stages of the 2011 conflict.
Ibrahim's sentence is the first of its kind handed down in the post-Gadhafi judicial system.
The International Criminal Court ruled against Libya in its appeal to try Saif al-Islam Gadhafi, Moammar Gadhafi's son, in national courts. He's suspected of committing crimes against humanity, including murder, during civil war in 2011.
The ICC said it wasn't convinced of Libya's assertion his surrender to The Hague would create problems for the government.
Libyan authorities say they have the right to try Gadhafi-era officials in national courts provided the national judicial system is open and functioning.