Our world is in crisis; with the impending doom of global warming, coupled with climbing global populations, and the growing demands of the world’s increasingly urban population, the need to reimagine our current food systems is evident. Rooftop urban agriculture offers a solution to this problem, making good use of the idle rooftop space that often goes unused in cities across the globe. However, the technology’s adoption seems to be stunted. In Toronto there are no solely commercial rooftop urban agriculture operations; this is surprising seeing as Toronto was actually the first city in North America to adopt the Green Roof Bylaw, which requires the construction of green roofs on all new developments over a certain size. While there has been extensive research done to investigate the environmental and social impacts of rooftop urban agriculture, the industry remains hindered. It had become clear that the technology’s ability to serve as a sustainable business opportunity was unsubstantiated, ultimately impeding its implementation on a wide scale. This research uses various business design tools to theorize, test, and illustrate the potential of open-air rooftop urban agriculture to thrive as a sustainable business.