Background Most existing research on medical clowns in health care services has investigated their usefulness mainly among child health consumers. In this research we examined multiple viewpoints of medical staff, clowns, and health consumers aiming to identify the optimal audience (adult or child health consumers) for which medical clowns are most useful. We focused on exploring their usefulness in enhancing health consumers’ satisfaction and, in turn, reducing their aggressive tendencies. Methods We conducted three studies that examined the placement fit of medical clowns from different points of view: medical staff (Study 1, n = 88), medical clowns (Study 2, n = 20), and health consumers (Study 3, n = 397). The main analyses in Studies 1 and 2 included frequencies and t-tests comparing perceived adult and child satisfaction with clowns’ performance. Study 3 used moderated-mediation PROCESS bootstrapping regression analysis to test the indirect effect of negative affectivity on aggressive tendencies via satisfaction. Exposure to the medical clown moderated this relationship differently for different ages. Results Studies 1 and 2 show that the majority of medical clowns and medical staff report that the current placement of the medical clowns is in pediatric wards; about half (44% of medical staff, 54% of medical clowns) thought that this placement policy should change. In Study 3, data from health consumers in seven different hospital wards showed that clowns are useful in mitigating the effect of negative affectivity on satisfaction, thereby reducing aggressive tendencies among health consumers under the age of 21.6 years. Surprisingly, medical clowns had the opposite effect on most adults: for health consumers who were exposed to the medical clown and were above the age of 21.6 negative affectivity was related to decreased satisfaction, and an increase in aggressive tendencies was observed. Discussion Medical clowns are most useful in elevating satisfaction and reducing aggressive tendencies of children. Older adults, on the other hand, exhibit lower satisfaction and higher aggressive tendencies following exposure to the performance of medical clowns. Conclusion Medical clowns should be placed primarily in children’s wards.