In the present study, plant essential oils were successfully extracted from the medicinal plant Pongame oiltree (P. oiltree) using the hydrodistillation method and found to possess excellent anti-biofilm properties against biofilm forming Acinetobacter baumannii (A. baumannii). GC-MS analysis confirmed the presence of all the essential oils in the crude P. oiltree extract. The agar well diffusion method of crude and HPLC purified fraction of the essential oils were showed anti-virulence behaviour instead of anti-bacterial activity. The anti-virulence metabolites were separately purified and confirmed by analytical HPLC. Subsequently, the minimum biofilm inhibition concentration and maximum biofilm inhibition concentration of the P. oiltree essential oils indicated 96 % biofilm inhibition against A. baumannii. In addition, the internal pathogenicity inactivation due to the HPLC purified essential oils was confirmed by inhibition of exopolysaccharide. The architectural biofilm damage with increased death cells and compromised external morphology with loss of original shape was validated by confocal laser scanning electron microscope and scanning electron microscope analysis. Overall, the present study suggests that the HPLC purified fraction of P. oiltree essential oils are an effective anti-biofilm agent against drug-resistant A. baumannii, and it is a future alternative drug discovered option to fight against biofilm-forming bacteria.