Endovascular interventions typically begin with the placement of a guidewire. Guidewire placement is challenging due to tortuous anatomy and the lack of steerability at the guidewire tip. Navigation often requires several guidewires with different stiffnesses to ensure the target is safely reached. This results in longer procedure times, extended radiation exposure to patients, and higher healthcare costs. To address these challenges, we present the design, modeling, and control of a tendon-driven robotically steerable guidewire with controllable stiffness along its proximal segment through a proposed motion control scheme. Models to capture the motion of the guidewire are presented and image feedback is utilized to achieve closed-loop control. The proposed controller exhibited maximum deflection RMSE of 1.82° and 0.70° for the distal and stiffening joints, respectively. The stiffening joint achieved the desired stiffnesses with a maximum RMSE of 1.9 × 10-2 Nm2. Thus, the methods presented in this paper demonstrate the potential to use a single guidewire in a procedure.