A piston assembly for an air spring includes an outer shell and a structural insert. The outer shell includes a side wall and an end wall at least partially defining a shell cavity having an open end. The structural insert is received in the shell cavity and includes a central portion and a plurality of support walls extending outwardly from the central portion toward the side wall of the outer shell. The central portion includes first and second opposing ends with the first end disposed toward the end wall of the outer shell and the second end disposed toward the open end of the outer shell. An air spring assembly includes such a piston assembly. A method of manufacturing an air spring assembly is also included.