Sustained innovation is a critical factor for enterprises to maintain their competitive advantages. Patient capital is a key institutional arrangement to address the maturity and risk mismatch between capital supply and demand in the innovation process, and its empowering mechanism and economic effect remain an urgent issue to be studied. Based on data from China’s A-share listed companies from 2013 to 2023, this paper finds that patient capital can effectively facilitate sustained innovation with a significant cumulative advantage effect. Mechanism testing indicates that patient capital empowers sustained innovation input primarily through two supportive pathways—resource effect and governance effect, and empowers sustained innovation output through two driving pathways—knowledge breadth expansion effect and innovation factor synergy effect. Heterogeneity analysis indicates that the empowering effect of patient capital is more pronounced in high-tech enterprises, mature-stage enterprises, technology-intensive industries, and enterprises located in the eastern and central regions of China. Economic consequences show that sustained innovation can generate significant excess returns for investors, verifying that the “patience” of capital indeed yields greater “value” over time. This paper not only provides insights for resolving the issue of innovation sustainability among enterprises, but also offers a theoretical basis and empirical support for fostering and expanding patient capital.