The environmental evaluation of the sorption-enhanced water–gas shift (SEWGS) process to be used for the decarbonization of an integrated steel mill through life cycle assessment (LCA) is the subject of the present paper. This work is carried out within the STEPWISE H2020 project (grant agreement No. 640769). LCA calculations were based on material and energy balances derived from experimental activities, modeling activities, and literature data. Wide system boundaries containing various upstream and downstream processes as well as the main integrated steel mill are drawn for the system under study. The environmental indicators of the SEWGS process are compared to another carbon capture and storage (CCS) technology applied to the iron and steel industry (e.g., gas–liquid absorption using MEA). The reduction of greenhouse gas emissions for SEWGS technology is about 40%. For the other impact indicators, there is an increase in the SEWGS technology (in the range of 7.23% to 72.77%), which is mainly due to the sorbent production and transportation processes. Nevertheless, when compared with the post-combustion capture technology, based on gas–liquid absorption, from an environmental point of view, SEWGS performs significantly better, having impact factor values closer to the no-capture integrated steel mill.