To realise their potential to lead in sustainability development, cities require both symbolic resources such as social capital and legitimacy and material resources such as financial and technical support. Recent research in urban studies has shown that cities overcome institutional barriers to urban sustainability by drawing on support from their wider environment. However, we argue that resource needs vary depending on whether cities spotlight or sideline sustainability. Drawing on in-depth interviews with sustainability managers in cities with variable seriousness about sustainability, and representatives of city networks and support organisations, we show that cities express different symbolic and material resource needs as well as means to acquire them. When cities express pragmatic needs, they seek to demonstrate political feasibility and look to peer cities for legitimation; when cities express progressive needs, they aim to push the boundaries of technical possibility and broadcast their achievements to the world. Since cities require dissimilar external support, skewed attention towards 'leading' cities in extant research limits our understanding of how cities can overcome institutional barriers to climate action, especially when these barriers are high. Our findings offer contributions to the literature on city strategies for climate change on the institutional drivers of urban sustainability.