Lung cancer is the second leading cause of cancer-related mortalities globally. Failure in diagnosis at early stages and limited effective chemotherapeutics has severely impeded the clinical management of patients suffering from lung carcinoma. At present, researchers across the world are focused on exploring biologically active natural products for treating various cancers, which can thus be further investigated for their chemotherapeutical potential. Coleus aromaticus is a common herb used in culinary practices and has previously been shown to possess various medicinal characteristics. In the present study, the anti-cancer effects of ethanolic extract of C. aromaticus leaves (EtOH-LCa) against non-small cell lung carcinoma (NSCLC) A549 cells were screened. It was observed that EtOH-LCa reduced the viability of A549 cells and obstructed the cell cycle progression in a concentration-dependent manner. Importantly, EtOH-LCa succeeded in instigating the production of reactive oxygen species (ROS) (p < 0.001) within A549 cells. The elevation in ROS levels was concomitantly followed by the disruption of nuclear morphology and the loss in mitochondria viability within A549 cells. In addition, EtOH-LCa was successful in increasing the activity of caspases-3, which further aided in increasing apoptosis. Most importantly, EtOH-LCa decreased NF-κB expression (p < 0.05) along with modulating mRNA expression of pro-/anti-apoptotic genes; Bax, Bad, Bcl-2 and Bcl-XL within NSCLC A549 cells. Collectively, it could be concluded that EtOH-LCa possessed considerable anti-cancer effects against NSCLC A549 cells; however, further molecular studies are warranted to completely establish the chemotherapeutical potential of EtOH-LCa.