Stereocomplex biopolymer compositions having tunable and improved mechanical properties and methods of making such compositions are disclosed. The biopolymer compositions include combinations of a matrix-forming polylactic acid comprising an essentially pure enantiomer and a tough polyester to form a polylactic acid matrix. The polylactic acid matrix is further combined with a base polylactic acid comprising an essentially pure opposite enantiomer of the first essentially pure enantiomer of the matrix-forming polylactic acid to form the stereocomplex.