Industrial branching proposed by evolutionary economic geographers exhibits robustness in illustrating the spatial emergence of new industries in regions. However, extant studies are primarily confined to a single type of industrial branching mechanism, such as spin-off or firm diversification, and biasedly equate them as regional endogenous and firm-centric processes, regardless of wider contextual embeddedness. Therefore, this paper seeks to take into account the contribution of multiple and multiscalar industrial branching mechanisms embedded in industrial nature and territorial contexts to emerging industries in regions, with a particular case study of biotechnology industries in Guangzhou, China. The emergence of biotechnology industries in Guangzhou during 1978–2019 is characterized by an overall fluctuating trend and recent remarkable expansion in the 2010s. The emerging process is driven by the combination of spin-off, start-up, and firm diversification, sourcing from actors across multilevel geographical scales (e.g., urban, regional, national, global). Multiple and multiscalar industrial branching mechanisms are rendered by the spatiotemporally contingent articulations among micro-level firm motivations, meso-level industrial nature, and macro-level territorial contexts, which is encapsulated in Guangzhou's strategic position in China's economic reform and opening-up in a gradual manner and Guangzhou's latecomer position in biotechnology development and industrialization. With an emphasis on moving beyond regional endogenous and firm-centric accounts, this paper aims to articulate actor-specific motivations with industrial and territorial embeddedness to gain a multilayered and context-sensitive understanding of the emergence of new industries in regions.