Membrane tension is a key mechanical regulator of cell signaling, morphology, and division. Whether cells can sustain spatial gradients in membrane tension, or whether such asymmetries are rapidly dissipated by long-range tension propagation, remains actively debated. Here, we use the tension-sensitive fluorescent probe FliptR to measure changes in in-plane membrane tension following localized optogenetic activation of RhoA in mitotic HeLa cells. We find that local RhoA activation induces a sustained, cell-scale gradient in FliptR lifetime, consistent with a cell-scale in-plane membrane tension gradient and tension elevation on the non-activated side. This gradient depends on an intact actin and microtubule cytoskeleton and is accompanied by polarized cytoskeletal remodeling, with cortical F-actin enrichment at the activation site and asymmetric microtubule growth on the opposite side. AFM tether-force measurements reveal increased tether forces upon activation, indicating locally enhanced membrane–cortex coupling at the activated side. A coarse-grained membrane chemical-potential model explains how spatially heterogeneous membrane–cortex coupling can maintain such gradients. Together, our findings show that cells can actively generate and sustain spatially patterned mechanical states through localized cytoskeletal signaling.