The other went to French actress Tsilla Chelton for her role as Nusret in the winning film, which is called "Pandoranin Kutusu" in Turkish. "Pandora's Box" is a story of alienation and isolation in modern Turkey, a theme explored when Nusret's children discover she is beginning to suffer from Alzheimer's disease.
The festival named Britain's Michael Winterbottom best director for his drama "Genova," set on Italy's northwest coast, where the port city acts as a catalyst for change in the lives of a family disoriented by bereavement.
American director Paul Thomas Anderson was awarded the Fipresci prize - a subordinate category - for his film "There Will Be Blood."
The festival's annual New Director award went to Chinese filmmaker Cao Baoping for his film "The Equation of Love and Death."
Iranian director Samira Makhmalbaf's film "Two-legged Horse" took the festival jury's special prize.
The best actor award went to Argentina's Oscar Martinez for his role in "El Nido Vacio" ("The Empty Nest").
Hugo Colace won the best cinematography award for his camera work in "El Nido Vacio."
Benoit Delphine and Gustave Kervern shared the award for best screenplay for the French movie "Louise-Michel."
Nineteen films vied for San Sebastian awards at the 10-day festival held in the northern Basque coastal city facing the Bay of Biscay.
American actress Meryl Streep and Spanish actor Antonio Banderas were honored on Friday with the Donostia Prize for a lifetime's work.
Donostia is San Sebastian's name in the locally spoken Basque language. This year was the 56th edition of Spain's top film festival.