An influence of processing temperature on structural, morphological, and chemiresistive properties of cerium oxide (CeO2) films, deposited on glass substrate by a spin-coating method and composed of nanocrystallites (NCs), has been systematically investigated and reported. As-deposited CeO2 films demonstrate the cubic polycrystalline crystal structure and mixed-agglomerated type of surface morphology with several crevices, elevating easy and deep percolation to gas molecules for enhanced adsorption-desorption process. Chemiresistive gas sensing performance of CeO2 films studied to various target gases and operating temperatures; demonstrates excellent selectivity, rapid response/recovery time signatures, and consistent operation repeatability to nitrogen dioxide (NO2) gas @200 degrees C, over other target gases, along with superior response repeatability. The response signature of sensor increases from 6% to 45% when NO2 gas ppm level is increased from 5 to 100. Chemiresistive change in the CeO2 film sensor in presence of NO2 gas has been studied thoroughly and explored using band model and impedance spectroscopy analysis.