Theoretical analysis is presented to characterize the dynamics of electrically injected single-defect photonic crystal vertical-cavity surface-emitting lasers. The analysis is based on a phenomenological dimensional reduction approach for modeling the photonic crystal defect mode cavity and yields analytical expressions to characterize the noise and small-signal modulation response. The simulation results indicate that the photonic crystal laser has a lower noise level and high-frequency modulation response compared with a conventional counterpart.