The Municipality of Sergio Osmeña Sr. is one of the 25 municipalities comprising the Province of Zamboanga del Norte. She was created by virtue of Republic Act No. 3697 dated September 14, 1963. 

        The municipality was carved out of the municipality of Piñan. The barangays that originally comprise the new municipality were Sibulan, Dampalan, Labag, princesa Lamaya and Marapong. Barangay Sibulan was the seat of the new municipal government. 

        The first appointed municipal mayor was Hon. Lorenzo Collera, a former official of the Philippine Constabulary. He was the first and only appointed Municipal Mayor of the town. In 1964 Bienvenido Andilab was elected Municipal Mayor. He served for 20 years until his untimely death on May 4, 1984. Hon. Benjamin D. Butanas, his Vice-Mayor succeeded and served the seat until EDSA Revolution in February 1986. Dr. Rudy A. Clamohoy acted as mayor-designate up to his appointment on January 18, 1988. 

        Then on May 11, 1998, the municipality elected new set of officials to administer the local government unit. These officials were overwhelmingly favored due to their utmost dedication for the development of the municipality as well as in serving the municipal constituents.