Okay, well. Obviously, Inspector Gadget can't be the man's real name. Whoever he was, he was a regular human who worked for the cops or whatever.
Well I think that while on the job, something happened to him. Some terrible accident. Some explosion or collapse that left him completely destroyed.
Once the cops found this, the chief (the guy in the show all of the time) decided to do something never before attempted. They used the newest and most secret technology to recreate this man with super human powers (sorta like the bionic man or whatever). They programmed this robot version of the inspector to look and sound just like him, even to think like him. He was programmed with the very best AI and all.
He continued working for the company, even watched over his niece and dog, just like the real human version did. The only problem with all of this was that he didn't die in the accident. No, the real human version survived, only he was changed.
The accident deformed him, warped his brain, and made him see things differently. Once he discovered that they had replaced him with a robot doppelganger, he swore to destroy it no matter what it took. They had taken his life away and replaced it with a robot, that they now call Inspector Gadget.
The human version decided to use everything he had and knew to fight against this robot version, and to do evil to the company that had ruined his life. He also changed his name. Now he is known as Dr. Claw. You never see his face because it is the face of Inspector Gadget, only deformed from the accident.
Credited to thegendra on deviantART