Storing grain by rehydration and ensiling has the potential to improve the digestibility. Characterizing the microbial communities may help understand silage fermentation, intervene in the fermentation process, and improve the quality. We evaluated the chemical composition, in vitro DM digestibility (ivDMD), lactic acid bacteria (LAB), spore forming aerobic bacteria, and yeasts populations in rehydrated corn kernel silage. The DM concentration of the ground corn was measured, and water was added to increase the moisture to 30%. Approximately 4 kg of rehydrated kernel were ensiled in experimental silos. Four replicates for each fermentation time at 5, 15, 30, 60, 90, 150, 210, and 280 d were prepared. The microbial communities were counted and BAL and yeasts were identified. According to the cluster analysis of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra, representative microbial strains were identified by sequence analysis of the full-length 16S rRNA gene for bacteria and the internal transcribed spacer (ITS) region for yeast. The highest DM loss was 7.6% after 280 d. The low concentration of water-soluble carbohydrates (20 g kg⁻¹ of DM) was not limiting for fermentation, however in pH and acid production occurred slowly. Storage of the rehydrated corn kernel silage increased ivDMD up to d 280. The bacteria population reached maximum growth after 15 d. A total of 178 bacteria were isolates. Fourteen different LAB species, 3 species of Enterobacteriaceae, and one Staphylococcus species were identified from the MRS medium. Homofermentative species dominated the fermentation. A total of 103 isolates were identified as yeasts. The species Hyphopichia burtonii, Wickerhamomyces anomalus, Issatchenkia orientalis, and Meyerozyma guilliermondii were identified from Dichloran Rose Bengal Chloramphenicol Agar. There was no significant difference in the yeast population. The spore-forming aerobic bacteria count reached a peak at d 30 of fermentation. Molds were detected until the d 15. This silage was dominated by LAB but showed slow decreases in pH values.