A catheter insertion device that allows for single-handed insertion of the catheter within the vasculature of the patient is disclosed. The catheter insertion device includes a handle, a needle cannula partially within the handle, a guidewire partially within the handle and the needle cannula, and a first actuator connected to the handle and the guidewire. The guidewire is movable relative to the handle in a distal direction away from the handle, and in a proximal direction towards the handle. A catheter assembly is removably coupled to the handle and is configured to slide on the needle cannula. A catheter hub may be connected to a proximal end of the catheter, and a catheter advancer base may be releasably connected to the catheter hub. The catheter insertion device may also include a needle support pivotally connected to the handle for supporting the needle cannula on a cantilever portion thereof.