Using atomic force microscopy, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy, the morphology and mobility of charge carriers in composite films with a thickness of no more than 500 nm obtained on the basis of a polyelectrolyte complex of chitosan and chitosan succinamide with addition of particles of carbon materials were studied and estimated. The following carbon materials were used: single-walled carbon nanotubes, graphene oxide, and carbon-containing sorbents with different specific surfaces (Carboblack C and Carbopack). Moreover, the studied materials in the form of films were used as a transport layer in the structure of field-effect transistors. The output and transfer characteristics of the transistors obtained were measured. According to the measurement results, the mobility of charge carriers, µ, ranges from 0.341 to 1.123 cm2 V–1·s–1, depending on the type of carbon material added. The best result was demonstrated by films based on a composite containing simultaneously single-walled carbon nanotubes and graphene oxide (μ = 10.972 cm2 V–1·s–1).