<p>This study aimed to determine an optimal nitrogen (N) management strategy for improving grain yield and quality in high-quality hybrid rice and to identify plant traits contributing to the improvements. Field experiments were conducted across four environments (two sowing dates × two years) to assess the effects of N rate and N split-application ratio on grain yield, yield attributes, grain quality traits, and leaf carbon (C) and N status in two high-quality hybrid rice varieties. Compared to a moderate N rate (165 kg ha^–1), a high N rate (225 kg ha^–1) did not increase grain yield and decreased eating quality in both varieties. Under the moderate N rate, increasing the ratio of basal N rate (from 3/10 to 5/10) while decreasing the ratio of N rate at panicle initiation (from 5/10 to 3/10) improved grain yield and eating quality in both varieties. The yield improvement was attributable to increases in panicle number and pre-heading biomass production, and the enhancement in eating quality was tied to lower leaf N content and higher leaf C:N ratio at maturity. Applying a moderate N rate alongside an increased ratio of basal N rate and a decreased ratio of N rate at panicle initiation serves as an optimized N management strategy for high-quality hybrid rice. This strategy can improve grain yield by increasing panicle number and pre-heading biomass production, while also improving eating quality by decreasing leaf N content and increasing the leaf C:N ratio at maturity.</p>