Bringing ultrafast temporal resolution to transmission electron microscopy (TEM) has historically been challenging. Despite significant recent progress in this direction, it remains difficult to achieve sub-nanosecond temporal resolution with a single electron pulse imaging. To address this limitation, here, we propose a methodology that combines laserassisted TEM with computational imaging methodologies based on compressed sensing (CS). In this technique, a twodimensional (2D) transient event [i.e. (x, y) frames that vary in time] is recorded through a CS paradigm. The 2D streak image generated on a camera is used to reconstruct the datacube of the ultrafast event, with two spatial and one temporal dimensions, via a CS-based image reconstruction algorithm. Using numerical simulation, we find that the reconstructed results are in good agreement with the ground truth, which demonstrates the applicability of CS-based computational imaging methodologies to laser-assisted TEM. Our proposed method, complementing the existing ultrafast stroboscopic and nanosecond single-shot techniques, opens up the possibility for single-shot, spatiotemporal imaging of irreversible structural phenomena with sub-nanosecond temporal resolution.