Poly(N-vinylcarbazole) (PVK) composites containing poly(3-hydroxybutyric acid) (PHB) were synthesized via in situ deposition. The oxidative polymerization of N-vinylcarbazole was carried out by dissolving different weight percentages (10, 20, 30, 40, and 50 wt%) of PHB using ferric chloride as an oxidant. The as-synthesized composites were characterized by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface morphology of the resulting composites was studied by transmission electron microscopy, and the biodegradability of the composites was tested by the Sturm method. The temperature-dependent DC conductivity of the synthesized composite films was measured, and the activation energy responsible for the conductivity was examined. The incorporation of PHB in the synthesis of PVK composites significantly increased the conductivity and biodegradability of the resulting products. Thus, the newly synthesized composites have potential applications in the biological, medical, and engineering fields.