This paper presents a magnetic tumbling microrobot design at the micro-scale with flexible operating modes. The microrobot has a dumb-bell shape whose largest dimension is 400 μm. When subjected to an exterior predefined magnetic field, the magnetic microagent performs a tumbling motion driven by the interacting magnetic forces and momentums. By switching the magnetic field during the motion cycle the agent is also able to perform a sliding locomotion that is useful for micromanipulation. The magnetic field providing the drive force is generated by a portable coil system consisting of five electromagnetic coils. Under the available driven field, the prototype has shown adaptable mobility through tumbling mechanism on various types of surface in both dry and fluid environments, and also shown pushing manipulation in viscous fluid. This manipulation force has been experimentally evaluated through testing with AFM tip and a micro force sensor and shown to be on the order of several μNs.