The proliferation of generative artificial intelligence (GAI) technology poses a fundamental challenge to the current design protection law system, which is based on the traditional premise that “creation is a uniquely human act.” With courts and administrative agencies in major countries consistently denying AI’s independent creatorship, the absence of clear criteria for determining “human creative contribution” to secure rights in AI-powered designs has created legal uncertainty. Previous research primarily focuses on categorizing outcomes, subsequently leaving a gap in providing a systematic analysis system that reflects the complexity of the creative process and the multifaceted nature of human intervention. To address this gap, this study focuses on human creative contributions to the formation of the “essential” elements of non-obviousness, which is a core element of design protection. Accordingly, thecreative acts of GAI are redefined into five categories, “human-led and assisted,” “human-directed and generated,” “rule-based and optimized design,” “co-creation and integration,” and “AI-driven and autonomous generation,” and analyzed from a legal perspective. An in-depth review of the potential scope of protection for each category and examination of recent legal and case law trends in major countries, including Korea, the United States, European Union, and United Kingdom, reveals that demonstrating a causal relationship between specific human interventions, such as selection, editing, arrangement, and rule design, and the unique impression of the final product is a key requirement for recognizing rights. Based on this, practical guidelines are presented, including specific supporting evidence (prompt history, version control logs, before-and-after comparison data, etc.) and proof strategies required for each type of creative act. Furthermore, this study proposes policy recommendations: in the short term, clarifying review guidelines based on the type of creative activity; in the medium term, legislating the obligation to notify users of AI use; and in the long term, discussing the need to introduce a new protection system for autonomously generative designs that fall outside the scope of current legal protection. The analysis of the creative “process” is expected to contribute to the establishment of a balanced intellectual property policy that promotes design innovation in the GAI era and effectively protects creators’ rights.