The quality of metal components manufactured by laser-based additive manufacturing technologies is governed by the process parameters. Moreover, the process parameters differ depending on the material used. In particular, direct energy deposition (DED) technology is vulnerable to the control of external environmental variables, and there are many process variables, such as powder characteristics and laser parameters, and thus many tests are required to determine the optimal parameters. In this study, an experiment was conducted to derive the conformity criterion of the DED process for metal powder (STS304L). First, the effects of laser energy output, laser header moving speed, powder feed rate, and gas feed rate on the DED process were studied. The experimental results showed that the deposition height decreased as the laser header moved faster and that the dilution ratio and the width of the heat-affected zone depended on the laser power and powder feed rate. Specimens were printed based on the process parameter values determined in the experiment, and tensile tests were conducted to analyze their mechanical performance.