There is a need for the development of advanced thermoplastic and metal hybrid composites structures in automotive, aerospace and biomedical applications to reduce weight and improve the properties of the constituent materials. Herein, a novel thermoplastic, polyketone (PK), was studied in aggressive hygrothermal condition, in order to understand and characterize the alterations in mechanical, chemical and thermal properties of the polymer in application. A novel polymer-metal hybrid composite fabrication process by mechanical interlocking was then developed, with PK and a chemically etched aluminum, to improve the barrier and structural stability of the PK material. The adhesion performance of the PK-aluminum composite structure was optimized and studied. Finally, various thermoplastics, polyethylene (PE), polypropylene (PP) and polyphenylene sulfide (PPS) were constructed with the mechanical interlocking adhesion mechanism to form novel thermoplastic-metal hybrid composites, and each hybrid composite system was optimized and studied.