Summary: A state space based self-tuning controller is proposed that incorporates a closed loop pole restriction principle. The plant matrices, Kalman gain and the states are estimated using a bootstrap method. The state feedback control design is based upon a modified LQ infinite-time control that restricts the closed loop poles within a user-specified disk in the \(z\)- plane to meet the maximum overshoot and the maximum settling time specifications. The control design is called only when the estimated closed loop poles with the fixed existing control rule move out of the specified disk. This approach reduces the computational requirement significantly and also increases the stability robustness by providing a piecewise time-invariant control.