The time‐dependent behavior of perovskite devices is one of the limiting factors for wide application of these materials in sandwich‐type or lateral optoelectronic device architectures. Despite abundant research on the topic, the exact mechanisms underlying the dynamics of device performance remain elusive. Herein, photoluminescence (PL) and electric field‐induced second harmonic microscopy techniques are combined to image and identify voltage‐induced lateral dynamic processes in methylammonium lead iodide perovskite thin films. A sequence of voltage‐induced dynamic steps is observed: i) Appearance of a short‐lived bright PL next to the positive electrode; ii) formation of a moving dark PL front; iii) emergence and blinking of bright PL spots; iv) growth and subsequent decay of the bright PL spots after voltage turn off. This behavior is explained by proposing a model of varying spatial distribution of inter‐electrode electric field and the presence of two types of PL quenching defects.