The disclosure herein provides repositionable medical instrument support systems, devices, and methods. A repositionable medical instrument support system comprises a frame for rigidly connecting the system to a patient support, a ball and socket joint configured to provide three degrees of rotational freedom, a frame mounting arm configured to releasably mount the ball and socket joint to the frame, a sliding joint configured to provide one degree of translational freedom, a connecting arm configured to connect the sliding joint to the ball and socket joint, and a docking member configured to engage a medical instrument to support the medical instrument during a medical procedure.