Approaches for the synthesis and processing of responsive materials that combine robust mechanical properties and the ability to undergo shape change in response to a stimulus are of intense interest. Here, we report an approach to integrate these properties by synthesizing liquid crystal elastomers (LCEs) that can be aligned and subsequently crystallized. We polymerize LCEs in the isotropic and nematic states and characterize the resulting actuation and mechanical properties. After polymerization, each of these materials can be reversibly crystallized. By crystallizing LCEs, we demonstrate stiffer and tougher shape changing materials. Notably, crystallized samples exhibit moduli 2 orders of magnitude higher and toughness times higher than nematic elastomers. Heating melts the crystallinity and then induces shape change via melting of the liquid crystalline phase. These LCEs are capable of high load bearing during actuation, up to 1.3 MPa, and high work capacity, up to 730 kJ/m(3). These aligned and crystallized LCEs offer promising benefits as dynamic smart materials with robust mechanical properties.