An optimal model-free controller and a linear controller are designed and applied to a horizontal magnetic micromanipulator for controlling microparticles in a liquid environment. An input–output relation based model for the magnetic micromanipulator is obtained, verified, and used in the analysis of controllers. A model-free linear controller is designed using the offset current approach. An optimal nonlinear controller based on Karush–Kuhn–Tucker conditions is designed and then modified to produce smooth control signals. Experimental results are provided to show the efficiency and feasibility of the proposed controllers. The model-free controllers yield short settling time and zero steady-state error in the control of magnetic microparticles.