Agricultural management practices alter soil characteristics and influence soil biological properties. Hence, a field trial was carried out to assess the 14-year long-term impact of tillage and residue management practices on soil biological activities and microbial population in a rice-wheat cropping system in two depths viz., 0-15 and 15-30 cm. Soil organic carbon levels differed significantly (p> 0.05) across various treatments. Microbial biomass carbon, Microbial quotient, and soil enzymatic activities were significantly greater (10-82%) in crop residue incorporation/retention treatments. Zero tillage with residue retention (ZT+R) had the greatest bacterial, actinomycetes, and fungi population, next to zero tillage with residue incorporation (RT+R). The ZT+R treatment had the greatest value of K-strategist and r-strategist, and was equivalent to RT+R across both soil depths. When compared to Conventional tillage (CT), zero tillage (ZT) increased wheat yield by 9%. However, compared to CT, rice and rice-wheat systems had lower grain yields, whereas crop residue increased wheat and rice-wheat system yields by 10% and 6%, respectively. The findings of this long-term study show that residue management and tillage practices can enhance soil biological attributes while also supporting microbial diversity.