Developing a low-cost, realistic room temperature operable acetone sensor is highly desirable in industrial and medical sectors for environmental monitoring and diagnostic purposes. The present study focuses on the simple co-reduction route to synthesize noble metal nanoparticle decorated reduced graphene oxide (rGO) and investigating the acetone sensing ability by using them as sensing materials to fulfil the requirements. Various spectroscopic and microscopic tools were employed to probe the structural and morphological details of the prepared materials. Gas sensing tests demonstrated the selective identification of acetone by the developed sensors, with the sensing materials exhibiting remarkable response at room temperature. The decoration of gold nanoparticles on reduced graphene oxide (AurGO) notably enhanced the response (1.87%) compared to pure rGO (0.65%). Despite a decrease in response with silver loading on rGO (AgrGO) (0.20%), sensors based on AgrGO exhibited rapid response and recovery times (49/38 seconds) compared to those of rGO (90/116 seconds) and AurGO (136/150 seconds). The acetone sensing mechanism is discussed in detail by predicting the band structure modification under the acetone exposure. The superior selectivity, repeatability, and long-term stability displayed by all the sensing materials suggest their cutting-edge applicability for real-world applications.