This study develops a cross‐level model examining the effects of intellectual capital facets (i.e., human, social, and organizational capital) on unit ambidexterity. Further, it proposes that organizational‐level high‐performance human resource (HPHR) practices significantly shape these effects as well as the unit ambidexterity–unit performance relationship. Hierarchical linear modeling on multisource and lagged data from a sample of 148 business units from 58 US Fortune 500 firms shows that unit human and social capital positively contributes to unit ambidexterity, unit organizational capital has a negative relationship with unit ambidexterity, and organizational HPHR practices amplify the former and mitigate the latter of these unit‐level effects. The findings also reveal that the relationship between ambidexterity and unit performance becomes stronger in organizational contexts of heightened HPHR practices. This multilevel approach increases understanding of how units achieve ambidexterity and attain related performance gains.