In this work, optimal operating policies for the industrial-level semibatch living free radical polymerization of styrene are proposed. Several operating scenarios are addressed, and one of the most promising ones is identified. The determination of the time-dependent optimal operating policies is posed as a dynamic optimization problem. The simultaneous dynamic optimization approach, involving the full discretization of the states and manipulated variables, was used to solve the resulting optimization problem. Moreover, the optimization problem also involved the determination of design parameters such as the initial holdup, feed stream temperature, and concentrations resulting in a large-scale nonlinear program. The resulting optimal operating conditions lead to a polymer featuring living characteristics matching monomer conversion, molecular-weight distribution, and polydispersity index target values.