This study investigated Lacticaseibacillus paracasei GV17, a potentially probiotic strain, in association with the commercial culture Streptococcus thermophilus STI-12, in lactose-free fermented milk. Predictive modeling was used to estimate growth parameters and microbial viability and the technological characteristics of the fermented milk during storage. The initial concentrations of the strains were 9.80 log CFU/mL for Lc. paracasei GV17 and 9.50 log CFU/mL for S. thermophilus STI-12. After eight hours, the pH reached 4.6, and the concentrations of GV17 and STI-12 were 10.90 log CFU/mL and 11.20 log CFU/mL, respectively. The Baranyi model was fitted to the growth data, with correlation coefficients of 0.760 for Lc. paracasei GV17 and 0.852 for St. thermophilus STI-12. The maximum specific growth rates were 0.912 log CFU/h for GV17 and 0.882 log CFU/h for STI-12. Regarding technological characteristics, syneresis decreased by 8.90% after 28 days, indicating greater structural stability, while water retention capacity remained constant. The viability of LAB remained above 10.00 log CFU/mL. Lc. paracasei GV17 showed great potential for use in functional products, prompting further research.