Improving alfalfa biomass yield production through an eco-friendly approach is crucial for sustainable agriculture productivity. A study was conducted at the University of Debrecen, Hungary, to examine the effect of biostimulant application on two alfalfa biomass yield performances and identify potential cultivar-specific responses to the biostimulant treatment. Two alfalfa cultivars, (i) Magor and (ii) Hunor, were subjected to biostimulant supply under field conditions, and biomass yield was harvested four times on a plot basis. The experiment was arranged in a randomised complete block design (RCBD) with four treatment combinations consisting of T0 = control, T1 Biostimulant containing MTU®, pidolic acid, and Si (2.5L/ha); T2 = Tricho Immun + Ino Green (foliar fertilizer) (3+3L/ha); and T3 = Tricho Immun (3L/ha) replicated three times. Our findings show significant differences in yield responses between the two cultivars following the application of biostimulant treatments with or without foliar fertilizer. Hunor exhibited a significant increase in biomass yield of 8.73% compared to 6.27% Magor across all the harvested periods. The application of biostimulants with or without foliar fertilizer significantly increases biomass yield production, highlighting differential responses based on cultivar genetics. The treatment applied attained biomass yield in the range of 17959 kg/ha to 19983.75 kg/ha, which contributed a yield increase of 1.10% to 11.27% for Magor, while 15534 kg/ha to 17347 kg/ha was observed for Hunor, contributing a yield increase in the range of 8.11% to 11.67%. Our results indicate that Hunor had a better yield response to biostimulant application compared to Magor. The study contributes valuable insights to optimizing alfalfa production strategies, focusing on the potential of biostimulants in enhancing alfalfa crop yield performances and agricultural sustainability.