In contrast to men, women are often assumed to bear the burden of making others feel comfortable through positive emotional displays such as smiling. However, in the literature, the empirical evidence for the relevance of gender stereotypes in explaining electoral outcomes remains inconclusive. By focusing on gender stereotypes regarding facial emotional displays, this study addresses the gendered consequence of candidates’ smiling on their electoral fortunes. I analyze the results of the 2014 Korean local elections and measure candidate smiles on campaign posters by employing a biometric artificial intelligence application detecting facial emotions in images. The results demonstrate that the smiling effect has a powerful positive impact on the electoral performance of women candidates running in a multicandidate race. The positive effect is limited for women running in two-candidate races and for male candidates regardless of the number of competitors. The findings suggest that voters use intuitive cues such as candidate facial displays in electoral posters when choosing among multiple candidates in low-information settings. This study contributes to a better understanding of the activation of gender stereotypes in the electoral process.