Following cardiac specification and differentiation, a complex choreography of cardiomyocyte cell behaviors generates the characteristic shapes of the cardiac chambers. Chamber shape can be sculpted by cell movement, cell division, or changes in cell size and shape, and all of these cellular activities can be influenced by the surrounding environment. Very little is known about the molecular and cellular mechanisms that regulate this elaborate process. By combining high-resolution live imaging with genetic analysis, we can elucidate pathways with a crucial influence on the actions of individual cardiomyocytes. To date, we have focused our attention on two particular steps of cardiac morphogenesis: the midline merger of the bilateral cardiomyocyte populations and the emergence of chamber curvatures. During both of these processes, regionally restricted patterns of cell behavior underlie key features of cardiac morphology.