Intensive winter wheat production in the North China Plain (NCP) is increasingly constrained by excessive nitrogen (N) inputs, groundwater depletion, and environmental burdens. Identifying an optimal water-N management strategy that balances productivity, profitability, energy performance, and environmental sustainability is therefore essential. A four-season split-plot field experiment was conducted under high–low seedbed cultivation (HLSC), with four N application rates (N1: 360, N2: 300, N3: 240, and N4: 180 kg N ha⁻¹) assigned to the main plots and three irrigation quotas (W1: 120, W2: 90, and W3: 60 mm) assigned to the subplots. Economic performance, energy budgets, environmental impacts, and eco-efficiency were jointly assessed to identify an eco-optimal management strategy (EOMS). Across the four growing seasons, N3W2 provided the best overall balance among crop productivity, profitability, energy efficiency, and environmental sustainability. Grain yield under N3W2 was statistically comparable to that under the higher-input treatments, while achieving the highest net income (1370.89 $ ha⁻¹) and benefit–cost ratio (1.61). Reducing N application from N1 to N3 decreased energy input by an average of 18.91% across irrigation levels, while N3W2 maintained a high energy-use efficiency (9.53). Compared with N1W1, N3W2 reduced the total normalized midpoint burden and total endpoint environmental damage by 25.9% and 24.1%, respectively. Fertilizer and irrigation were the dominant contributors to environmental burdens, jointly accounting for 91.3% of the summed normalized midpoint burden. N3W2 also achieved the highest endpoint eco-efficiency (2.20 $ Pt⁻¹), demonstrating that coordinated reductions in water and N inputs can improve economic and environmental performance without a significant yield penalty. Overall, coupling 240 kg N ha⁻¹ with 90 mm irrigation quotas provides a practical EOMS for HLSC-cultivated wheat in the NCP and other regions with comparable conditions.