Cytoskeletal motors are involved in a vast array of cellular processes, including motility, cargo transport, and force generation. Molecular engineering stands as a useful tool to interrogate the determinants of motor protein activity. Moreover, in order to harness these molecular machines for nanotechnological functions, as well as to perturb the cellular functions dependent on these motors, I have endeavored to develop novel methods of control over the motion generated by both actin- and microtubule-based motors. I first undertook a dissection of the determinants of directionality in an actin-based motor, myosin VI. Based on these results, we were able to identify a strategy for dynamic control over myosin VI directionality based on reversible transitions between rigid and flexible structural states of a portion of the myosin lever arm. We created a calcium-sensitive bidirectional myosin as an initial demonstration of this strategy by fusing calcium-sensitive calmodulin-binding domains to the lever arm. We subsequently extended lever arm engineering to encompass light control through the incorporation of a light-sensitive protein domain (LOV2) into the lever arm of myosin. Junctional variants and computational design yielded constructs that speed up, slow down, and switch directions in response to blue light. To test the generality of our optically-controlled design, we fused our engineered lever arm to myosin XI to create controllable myosins with high velocities, and to kinesin-14 (Ncd) to create controllable microtubule-based motion. These engineered motors could serve as the basis for components of nanoscale devices or for optogenetic control over cytoskeletal motor function in living cells.