B757 Captain reported a hydraulic malfunction during climb. The flight returned to the departure airport; landed overweight; and was observed to be leaking fluid on the landing gear.

Narrative

On climb out we received a L HYD QTY EICAS Message. We pulled up the status page and we notice the L hyd qty at .46 with a RF (Refill Indication) showing next to the number. We accomplished the L HYD QTY checklist and called dispatch and Maintenance Control. During that call the hyd fluid qty was steadily decreasing even with the left hyd pumps deactivated per the checklist. We decided to return to ZZZZ and requested priority handling. Hyd fluid qty continued to decrease for the rest of the flight and settled around .18. We descended early to get configured early. As per the checklist we reactivated the left system hydraulic pumps and put the gear down normally; upon doing that we lost the rest of the hydraulic fluid and got the L HYD SYS PRESS EICAS message; but the gear was down and we had a three green indication with a GEAR DOORS EICAS. This was expected and we continued with the L HYD SYS PRESS checklist and we accomplished a uneventful flaps 20 overweight landing. We had told emergency services that we may not have nose wheel steering and we may need to be towed off. Upon landing we still had nose wheel steering so we exited the runway under our own power. Emergency services told us on inspection that our gear doors were still open and had fluid leaking on our right main landing gear. We taxied to a remote parking stand and we had nose wheel steering until we attempted to turn into the parking space and we lost nose wheel steering. I used differential braking and thrust to go the rest of the way into parking approximately 100-150 feet. We parked and deplaned without incident.