Fusarium wilt, caused by Fusarium spp., is considered one of the most serious diseases affecting pico chrysanthemum (Chrysanthemum spp.), leading to significant yield and quality losses. This study was conducted to identify the fungal pathogen causing wilt disease in pico chrysanthemum and to assess the antifungal potential of Bacillus spp. under in vitro conditions. The fungal isolate FC1 was recovered from infected plants and identified as Fusarium keratoplasticum through analysis of internal transcribed spacer (ITS) gene sequences together with morphological characteristics. Its pathogenicity was confirmed in accordance with Koch’s postulates. All 41 Bacillus isolates exhibited antifungal activity against F. keratoplasticum in dual culture assays, with mycelial growth inhibition ranging from 20.0% to 52.2%. Volatile organic compounds (VOCs) and cell-free supernatants (CFS) produced by six promising isolates (CB3, CB10, CB31, CB32, CB35, and CB36) markedly suppressed both mycelial growth and spore germination of fungal isolate FC1. These findings suggest that the selected Bacillus isolates have strong potential as biological control agents for managing F. keratoplasticum-induced wilt in pico chrysanthemum.