Human blood is one of the most valuable and irreplaceable goods in modern medicine. Although its necessity increases daily, one of the most significant challenges we have to overcome is a scarcity of willing blood donors. Volunteer motives and attitudes have been studied for decades, but it is now considered vital to grasp the many aspects that will increase the effectiveness of attracting new blood donors. This study focuses on the impact of emotional arousal produced by advertising messages, as well as the determining role of altruistic and egoistic incentives in deciding behavior. We also incorporated the element of personality to investigate how personality traits influence behavioral intention to donate blood. To this end, a quantitative non-experimental correlational 2 × 2 experimental design (positive vs. negative emotional appeal; altruistic vs. egoistic message) was implemented with the participation of 462 respondents who were shown a total of 12 advertisements (ads) promoting blood donation. The data were analyzed using structural equation modeling, with a focus on the direct impacts on donation intentions, the role of emotional arousals and attitude towards the ads as mediators and the moderating effect of the message. The empirical results of our hypotheses revealed that only Honesty-Humility had a strong direct impact on behavioral intention to donate, while Emotionality and Agreeableness did not have any direct effect. On the other hand, attitudes towards advertisements significantly and directly influenced positive and negative emotional arousals, respectively. Furthermore, if we consider these two variables alone, they can be found to exert a direct impact on BI. Mediation analysis showed that attitudes towards the advertisements and emotional arousals partially mediated the relation between Honesty-Humility and Behavioral Intention, thus confirming partial mediation. With respect to Emotionality and Agreeableness, mediation was found to be full since these factors only affected BI through a mediated path, which confirmed full mediation. Furthermore, the moderation analysis highlighted that the type of message (altruistic vs. egoistic) significantly moderated the relationship between both emotional arousals and BI. In particular, positive emotional arousal's influence is strengthened when it is aligned with altruistic messages, while negative emotional arousal's influence is weakened if it follows an altruistic message. These findings illustrate that using positive emotions will be more beneficial for increasing people's donation intentions than bringing negative ones, which implies that message framing has a hidden impact on donation decisions.