Aims <p>While subsurface irrigation with ceramic emitters has been recognized as an efficient technique for stabilizing soil moisture, enhancing water-use efficiency, and boosting crop productivity, its potential for synergistic nitrogen management remains underexplored. We introduced an innovative continuous micro-nitrogen supply (CNS) method, leveraging the intrinsic microporous structure of ceramic emitters to achieve steady, low-dose fertilization. This study aimed to investigate the effects of CNS on soil nitrogen distribution characteristics, tomato growth, yield and nitrogen utilization efficiency.</p> Methods <p>We conducted a greenhouse experiment comparing intermittent (INS) and continuous nitrogen supply at four concentrations, assessing their effects on tomato growth, yield, fruit quality, and nitrogen use efficiency (NUE). Soil nitrogen dynamics were simulated using the HYDRUS-2D model, while the TOPSIS method identified the optimal nitrogen concentration.</p> Results <p>Results demonstrate that CNS maintains a more stable soil nitrogen environment and elevates average soil ammonium and nitrate nitrogen contents compared to INS. CNS improved tomato biomass accumulation, increased yield by 9.29%, and enhanced key NUE indices—partial factor productivity (10.45%), physiological utilization efficiency (4.72%), and absorption efficiency (5.50%). The optimal strategy, CNS210, balanced yield gains with minimal environmental risks.</p> Conclusions <p>Our findings highlight the potential of CNS as a precise nitrogen delivery method in greenhouse systems and help improve water and fertilizer use efficiency.</p>