We report the facile and green synthesis of activated carbon-supported palladium (Pd/AC) containing homogeneously dispersed Pd nanoparticles (Pd NPs) by using eco-friendly and naturally available cinchonidine (CD) as the capping agent. The Pd NPs in the synthesized Pd/AC hybrid are uniform with sizes predominantly in the range 4 to 7 nm. The synthesized Pd/AC was characterized with various methods, such as TEM, XRD, and XPS, and the influence of the synthetic conditions on its properties were investigated. The advantages of CD over conventional capping agents include its easy depletion after the synthesis with a simple rinsing process. Owing to the ultrafine, well-dispersed and purified Pd NPs, the synthesized hybrid exhibits excellent catalytic activities in the reduction of 4-nitrophenol and methylene blue. These findings further the development of novel stabilizing agents from naturally available sources for the preparation of heterogeneous catalysts with enhanced performance.