We use ultrafast spectroscopy to study and control the excited-state dynamics of a common photochromic molecular switch. The compound undergoes reversible electrocyclization and cycloreversion reactions that convert the molecule between open- and closed-ring states with very different electronic and optical properties. Our experiments use various excitation schemes to explore different regions of the excited-state potential energy surfaces in order to probe the non-adiabatic dynamics of both the forward and reverse reactions. The dynamics of the ring-closing reaction are complicated by the presence of non-reactive conformers that are in equilibrium with the reactive species. The electronic dynamics of the non-reactive conformers include efficient intersystem crossing, which has important implications for avoiding unwanted photochemistry that permanently damages the molecule. We find that subtle modification of the photoswitch structure dramatically affects triplet formation, as well as the photochemical stability of the compound over many photoswitching cycles. Other measurements use sequential two-photon excitation to probe the excited-state dynamics of the ring-opening reaction. In these experiments, we selectively control the reaction path by re-exciting the molecule from one excited state to a higher state. Allowing the molecule to evolve on the first excited state for a short period between excitation pulses leads to a substantial increase in the reaction yield compared with one-photon excitation, and allows us to map out the dynamics of the cycloreversion reaction.