Prior literature examining the antecedents of employee affect has largely ignored subtle affective influences in the workplace and their impact on employees' affective experiences and behaviors. A substantial body of evidence from basic psychology research suggests that individuals' affect can be influenced by minimal stimulus input. The primary objective of this research is to take an initial step towards understanding the “real‐world” impact of subtle affective stimuli in the workplace. Specifically, in a field experiment with a within‐subjects design, we collected data from 68 sales representatives and examined the effect of a subtle affective stimulus (i.e., a black‐and‐white picture of a woman smiling printed on the backdrop of paper–pencil surveys) on employees' affect, well‐being, and performance. Results showed that the smiling picture significantly enhanced participants' positive affect, which in turn influenced employees' extra‐role performance and emotional exhaustion. The smiling picture also indirectly influenced employees' in‐role performance and emotional exhaustion via negative affect. Theoretical and practical implications of these findings are discussed at the end of the paper. Copyright © 2017 John Wiley & Sons, Ltd.