<p>In this paper, we investigate the dynamics of the nucleating scalar field during the first-order phase transitions by incorporating one-loop corrections of classical fluctuations. We assume that a high-temperature expansion is valid — where the mass of the scalar field is significantly smaller than the temperature — so that we can treat the bubble-wall dynamics in a regime where quantum fluctuations can be integrated out. We present a systematic framework for calculating classical loop corrections to the wall speed; contrast our results with traditional methods based on the derivative expansion; show that the latent heat can differ from the effective-potential result; and discuss general hydrodynamic corrections. Finally, we show an application of the presented framework for a simple scalar field model, finding that the one-loop improvement decreases the wall speed and that an effective-potential approximation underestimates full one-loop corrections by about a factor of two.</p>