Prior reward is a potent cue for attentional capture, but the underlying neurobiology is largely unknown. In a whisker touch detection task, we show that mice flexibly shift attention between specific whiskers on a trial-by-trial timescale, guided by the recent history of stimulus-reward association. Two-photon calcium imaging and spike recordings reveal a robust neurobiological correlate of attention in the somatosensory cortex, boosting sensory responses to the attended whisker in L2/3 and L5, but not L4. Attentional boosting in L2/3 pyramidal cells is topographically precise and whisker-specific, and shifts receptive fields toward the attended whisker. L2/3 vasoactive intestinal peptide (VIP) interneurons are broadly activated by whisker stimuli, motion, and arousal but do not carry a whisker-specific attentional signal, and thus do not mediate spatially focused tactile attention. These findings provide an experimental model of focal attention in the mouse whisker tactile system, showing that the history of recent past stimuli and rewards dynamically engage local modulation in cortical sensory maps to guide flexible shifts in ongoing behavior.