The role of interstitial carbon impurities on the dislocation glide in bcc iron is investigated by means of molecular dynamics simulations. The local stress induced by carbon atoms, interaction energy map for the a0/2 <111>{110} and a0/2<111>{112} edge dislocations and the dynamics of dislocation–carbon interaction is assessed. The local stress exerted on the dislocation due to the carbon atoms and computed by atomistic simulations is used to describe the interaction strength on the continuum level. The derived here analysis of the atomistic data enabled the determination of the activation enthalpy and volume as a function of stress. Having that information, a comparative study demonstrates that at finite temperature, the resistance to the dislocation glide induced by the carbon atoms is lower in {112} than in {110} slip systems.