The Interpretation of "Substantial Control" in the Proviso to Article 2(2) of the Amended Trade Union and Labor Relations Adjustment Act － Focusing on a Comparison with the Doctrine of Employer Status under the Japanese Labor Union Act －

This article examines the interpretation of the proviso newly added to Article 2(2) of the Korean Trade Union and Labor Relations Adjustment Act, focusing on the employer status of entities that are not direct parties to an employment contract but are in a position to substantially and specifically control or determine workers’ working conditions. Although the amendment seeks to impose employer responsibility on such entities within the scope of their actual control in multi-layered employment structures, the concrete criteria for determining “substantial control” remain uncertain. For this purpose, this article conducts a comparative analysis of Japanese case law and legal theories on employer status under the Japanese Trade Union Act, including the development of the control theory, the labor contract standard theory, and the concept of partial employer status established through the Asahi Broadcasting case. The Japanese experience demonstrates that employer status cannot be determined solely by the existence of direct command and instruction. Rather, the inquiry must be structured according to specific working conditions and types of user entities. Based on this comparative analysis, this article identifies structural control over working conditions as the core element of substantial control under the amended Korean Act, while also proposing business integration, economic dependence, and the necessity of collective bargaining as supplementary factors. It further classifies the application of these criteria by user type, including in-house subcontracting and ordering companies, parent or holding companies, public outsourcing, logistics and platform-based work, and retail facility operators. In addition, in light of the recent Supreme Court en banc decision, this article argues that the scope of employer status should be differentiated according to the type of unfair labor practice at issue. In conclusion, the employer status of a non-contractual user should be understood not as an abstract and comprehensive status, but as a partial and functional concept linked to specific working conditions and specific types of unfair labor practices.