This paper proposes a robust proportional-integral (PI) controller design for multivariable complex processes to achieve both well-decoupled and well-damped output behavior. By reformulating PI-controlled processes in a way similar to the LQG/LTR control design problem; the proposed model matching technique in the first design stage successfully results in the robust PI controller with well-decoupled output behavior and sufficient stability. Moreover, control performance can be further improved to achieve well-damped responses by applying gain modification in a second design stage. Both simulated results using chemical processes and experimental results using a wind tunnel have proven the feasibility of the proposed PI controller design in real applications.