Labyrinth weirs have become popular dam spillway control sections because they can pass larger flows than straight weirs in the same spillway footprint. Additionally, labyrinth weirs with multiple crest elevations, or stages, can be designed to meet several hydraulic goals. For example, a three-stage labyrinth may pass small baseflows on the low-stage, store the majority of moderate storm volumes, and pass extreme storm flows without overtopping an embankment. With this level of control, labyrinth spillways act as passive (no human action required during event) alternatives to automated or manually operated gate systems. For small to moderate size dams, a passive spillway is preferable because full-time staffing is not typically available and the spillway is able to operate even if staff cannot access the dam during a storm event. However, labyrinth weirs are more time intensive to design because there are many more design parameters than traditional straight weirs. For example, constant elevation straight weirs can be defined by height and width, whereas single-stage labyrinth weirs are typically defined by height, cycle width, cycle depth, apex length, and number of cycles. If multi-stage weirs are considered, the number of parameters can expand from 5 to 15. Educated guess and check methods are commonly used by dam engineers to select parameters that meet the hydraulic criteria for baseflows, moderate storm flows, and extreme flows. The complex interrelationships of hydraulic, structural, geotechnical, and construction-related considerations make the selection of parameters more challenging. For example, a tall weir passes more flow, but requires taller structural walls and consequently results in greater construction costs. Here, we present a case study using a combination of the optimization and automation software modeFRONTIER, empirical labyrinth flow calculations, cost calculations, and USACE’s HEC-HMS hydrologic modeling software to efficiently identify optimal labyrinth weir designs. In particular, we show an example parametric design optimization of a reinforced concrete labyrinth spillway considering the associated structural, geotechnical, hydraulic, and construction implications. This case study highlights the importance of interdisciplinary design and the impacts of system-level design optimization. It identifies the following benefits of this method: (1) Optimization algorithms can produce an equally efficient design in less time than guess and check methods; (2) In some cases, more efficient spillway designs can be identified than traditionally feasible. (3) Because the workflow is automated and modular, it is straightforward and fast to re-optimize the design if the stakeholders’ goals or assumptions change. For example, if material costs change, the design team can rapidly find the new optimal design variation; and, (4) Because the computational workflow can be depicted in an objective flowchart, the design assumptions and steps can be clearly documented improving traceability. The case study also identified the following potential challenges: (1) These methods should be employed early in the design process when system-level design considerations are better tolerated, and therefore, project teams must develop their schedules to allow for the setup of this type of tool; (2) Early coordination between subject matter experts is necessary to define the design workflow and its underlying methods. For projects with well-connected project teams, these challenges can be overcome, and substantial benefits are obtained from the system-level multi-disciplinary spillway optimization. For the case study presented here, the engineer’s team leveraged a well-connected technically diverse project team and customizable optimization/automation software to help connect the different disciplines for an efficient parametric labyrinth weir spillway optimization.