Generative Artificial Intelligence (GenAI) is increasingly explored for its potential to support educators during the early phases of learning design before implementation. This systematic review examines how GenAI functions as an Inspiration Hub, Enquiry Analyst, Design Tutor, Prototyping Consultant, and Co-design Facilitator across key pre-implementation phases of the learning design cycle: Introduction and Preparatory, Investigating, Conceptualizing, and Authoring. The study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to ensure a structured and reproducible approach. The review categorizes existing literature based on the type of evidence presented: exploratory, theoretical, confirmatory, and speculative, providing insights into the extent to which GenAI’s effectiveness in learning design is empirically supported. Additionally, the study explores documented examples of GenAI use cases in learning design, highlighting practical applications across different educational contexts. Findings reveal that research predominantly focuses on GenAI’s role in the Conceptualization and Authoring phases, with comparatively limited attention to its application in early-stage investigative and preparatory tasks. Furthermore, most studies present exploratory evidence, indicating a need for more solid empirical validation. By mapping GenAI’s reported roles to different stages of the design process and analyzing real-world use cases, this review contributes to a deeper understanding of AI-driven pedagogy and highlights gaps for future research on integrating GenAI into the learning design.