This research aimed to assess the impact of probiotic supplementation in the broiler diet on growth performance, nutrient utilization, noxious gas emissions, excreta micromiota and meat quality. One thousand six hundred and twenty male Ross 380 broilers (one‐day‐old, body weight, 42 ± 0.5 g and 5‐week trial) were arbitrarily chosen and assigned to three nutritive treatments (basal diet and basal diet included with 0.1%, and 0.2% probiotic mixture [Bacillus subtilis 7.0 × 107 cfu/g, Bacillus licheniformis 4.1 × 107 cfu/g]) with 30 duplicates (18 birds each). Probiotic inclusion linearly increased (p < 0.05) broiler body weight gain (BWG) during Phases 1, 2 and the overall period and decreased (p < 0.05) feed conversion ratio (FCR) linearly on Phase 2 and the overall period. However, feed intake (FI) and mortality rate remained unaffected (p > 0.05). Though nutrient digestibility of nitrogen (N) tendency to increase (p < 0.05), dry matter (DM) and energy (E) did not influence (p > 0.05). Inclusion of a probiotic supplement linearly increased (p < 0.05) Lactobacillus and reduced Salmonella (p < 0.05) counts in broilers. Moreover, broilers fed a diet supplement with probiotic addition linearly decreased (p < 0.05) NH3, H2S, C2O and acetic acid emissions. The graded level of probiotic addition linearly reduced (p < 0.05) cooking loss and the tendency to decrease (p < 0.05) weight of bursa of Fabricius, but had no effect (p > 0.05) on other meat quality measures. These findings indicated that increasing the level of probiotics in feed could improve growth efficiency, nutrient absorption, microbial index, meat quality and reduce gas emissions in broilers.