We advance understanding of the role of ability-based emotional intelligence (EI) and its subdimensions in the workplace by examining the mechanisms and context-based boundary conditions of the EI-performance relationship. Using a trait activation framework, we theorize that employees with higher overall EI and emotional perception ability exhibit higher teamwork effectiveness (and subsequent job performance) when working in job contexts characterized by high managerial work demands because such contexts contain salient emotion-based cues that activate employees' emotional capabilities. A sample of 212 professionals from various organizations and industries indicated support for the salutary effect of EI, above and beyond the influence of personality, cognitive ability, emotional labor job demands, job complexity, and demographic control variables. Theoretical and practical implications of the potential value of EI for workplace outcomes under contexts involving managerial complexity are discussed.