Today, designers are increasingly expected to engage with real-world complexities and act as creative change-makers, particularly in the context of social innovation. Designers’ capabilities in tackling such challenges deserve a closer examination. This study defines the implicit and generative capabilities in social innovation practice as “design attitude.” Through empirical research, it aims to articulate these elusive capabilities in detail and categorize their various dimensions into major types. This research explores how the interaction between design skills and design attitude shapes the capabilities needed for social innovation practice. Using Nice Commune, a social innovation network in Shanghai, China, as a case study, data were collected through workshops with professional designers and semi-structured interviews with non-designer stakeholders. A qualitative analysis, employing thematic analysis and grounded theory coding methods, reveals that design capability in social innovation is a synthesis of professional skills with design attitude. This study identifies the key dimensions of design attitude, which include valuing communication, empathy, presence, ambiguity tolerance, holistic thinking, connecting diverse perspectives, knowledge sharing, creativity, and aesthetic engagement. This research contributes theoretical knowledge to the role of designers when engaging with broader social practices.