We study the flexible flow shop scheduling problem with the heterogeneous worker assignment. Inmany real-life manufacturing systems with flow shop environments, one of the fundamental schedulingchallenges that needs to be addressed is job sequences across multiple workers. In addition, the manufacturingsystem may require workers to have different skills at various stages during their assignment. Therefore, workeravailability at each stage may vary during the scheduling horizon. Unlike traditional flexible flow shopscheduling problem, where homogeneous workers are assumed, we consider workers with different skill levels,capabilities, and capacities. We present a mixed integer linear programming model to find the optimal sequenceof job assignments, guaranteeing that jobs follow their predefined operation sequence while assigning workerswith various skill sets in a flexible flow shop environment. The proposed model is tested at a batterymanufacturing company. By analyzing the solution, we confirm its capability to represent the problemaccurately. The proposed model offers a systematic scheduling approach for a flexible flow shop environmentwith a heterogeneous workforce and can be implemented in other industries.