The success of small, medium, and micro enterprises (SMMEs) is especially important for increasing employment and economic growth that is sustainable in developing nations. SMMEs are reported to be more successful if they use particular business management strategies compared with those that do not implement such strategies. Service-learning projects (S-LPs), in the form of student-led advertising agencies (SLAAs), can assist SMME clients (community partners) with customer research, knowledge transfer and skills training, advertising, and marketing and business services, as well as provide students with practical experience. However, most research is directed at the student benefits, and few empirical studies investigate the advantages for the clients. Therefore, the main objective of this inquiry was to examine SMMEs’ satisfaction in terms of the perceived influence of a SLAA S-LP on lasting impact and business performance. A total of 107 SMME clients were surveyed via a structured questionnaire. The findings indicated that the SLAA S-LP had a significant positive influence on the lasting impact, and business efficiency, brand awareness, competitive advantage, employee motivation, customer loyalty, new customers, and sales of the participating SMMEs. Therefore, the SLAAs provided the SMMEs with low-cost marketing and advertising options that improved the performance of their businesses.