Like many cities with an abundant legacy of heritage structures and aspirations to expand their economic and population base, Halifax (Nova Scotia) experiences significant tensions between heritage conservation and urban development ambitions. On the one hand, Halifax has a vigorous heritage movement spawned in the wake of slum clearance and urban redevelopment efforts in the 1960s; heritage advocates work consistently to conserve the low-rise character of the historic city. On the other hand, it has an emergent urban design lobby supported by economic development interests and creative class ideas; development advocates call for signature high-rise buildings to attract investment and young people. With each new development proposal, community groups argue about the meaning of past and future, the nature of cultural identity and the image of the city. In this essay we examine the recent emergence of a social network of young urban professionals whose influence is growing rapidly in local debates about urban regeneration. Whereas a decade ago heritage conservation enjoyed high priority in planning debates in many parts of the world, today it competes with arguments for signature architecture and greater urban density. The urban design turn reflects changing cultural priorities but also reveals the operation of new governance mechanisms within local growth machines.