China is currently at a critical stage of advancing industrial upgrading through new quality productive forces and accelerating the achievement of high-level self-reliance and self-strengthening in science and technology. The deep integration of talent, capital, innovation, and industrial chains has become a key means of bridging the “last mile” of innovation and overcoming “bottlenecks” in critical technologies. Adopting an outcome-oriented perspective, this study defines the essential connotation of the “deep integration” of the four chains and develops a sequential analytical framework. Using data from Chinese listed firms from 2011 to 2024, 179 industrial chains are constructed to empirically examine, at the firm level, the transmission mechanisms, lagged effects, and heterogeneity of the “deep integration” of the four chains. The results show that, first, talent and capital support the innovation chain, enabling its successive stages to significantly promote industrial chain upgrading and thereby facilitating the “deep integration” of the four chains. Second, transmission across the stages of the innovation chain exhibits significant lagged effects, with the magnitude of the effects gradually diminishing as the lag length increases. Third, heterogeneity analysis reveals that the “deep integration” of the four chains is more pronounced in central and western regions, non-state-owned enterprises, and those in the midstream segment of industrial chains, with particularly strong marginal effects in central and western regions. Based on these findings, this study proposes three policy implications for advancing the “deep integration” of the four chains:first, to address “insufficient factor coordination” at the front end of R&D, talent, fiscal funding, and private capital should be directed toward basic research and “breakthroughs” in frontier technologies. Second, to alleviate bottlenecks in the commercialization of innovation outcomes, a phased support mechanism covering “R&D-pilot testing-industrialization” should be established, with pilot-testing platforms, cost-sharing arrangements, and market-access mechanisms used to bridge the “last mile” of technology commercialization. Third, differentiated and targeted policies should be implemented to address integration gaps across regions, ownership types, and industrial chain segments, thereby strengthening innovation catch-up in central and western regions, promoting complementary strengths between state-owned and private enterprises, and facilitating coordinated upgrading across upstream, midstream, and downstream segments.