Display omitted •Provides a detailed process optimisation of a formula of fermented finger millet.•The formula exhibits anti-proliferative and anti-migratory effects in HCT116 and MDA-MB-231.•Shows increased expression of Bak and decrease in full-length Bcl2 expression. The objective of this study was to optimise the millet formulation using Levilactobacillus brevis and to evaluate its anticarcinogenic potential in vitro. The formula was developed in the course of the fermentation of finger millet (Eleusine coracana) using L. brevis MTTC 4460 and optimised by response surface methodology and validation by artificial neural networking (ANN). The optimised millet formulation could be obtained using 2 % of bacterial inoculum, 2 % of glucose, and a fermentation duration of 3.3 days with a yield of 5.98 mg/mL lactic acid and 3.38 log10 (CFU/mL) viable L. brevis with overall desirability value of 1. The fermented millet formulation exhibited antiproliferative and antimigratory effects on MDA-MB-231 and HCT116 cancer cell lines. In addition, the outcomes observed in western blot analysis revealed that the formulation elicited apoptotic responses mediated by the Bcl-2 family of proteins in MDA-MB-231 and HCT116 cell lines while demonstrating no discernible impact on HEK293 normal cells.