The dynamics of hot luminescence of a vibronic system driven by a quasi-resonant, coherent laser field is studied in a nonperturbative manner. Analytical solutions for the temporal evolution of the line intensities are derived in the case of fast vibrational relaxation. In particular, it is shown that in transient observation schemes the intensity of the hot luminescence can exceed its small stationary value by a few orders or magnitude provided that the driving field is sufficiently strong.