Errol Woodger broke into a block of flats in Erith, south-east London, in the early hours of December 29 2019, the Old Bailey had heard.
He was disturbed by resident Marc Allen, 50, and snatched his keys before making off in his car.
When Mr Allen tried to stop him, Woodger used the car “as a weapon” to run him over, prosecutor Anthony Orchard KC had said.
Neighbours found Mr Allen in the road with a severe head injury, from which he died a month later, having never regained consciousness.
Woodger, 38, of Belvedere, south-east London, had claimed he was only a passenger in the vehicle driven by an accomplice who had since died from a drug overdose.
A jury at the Old Bailey rejected his version of events and found the former soldier, who served in Afghanistan, guilty of manslaughter and robbery.
Woodger had clapped in the dock as he was cleared of the more serious offence of murder on Tuesday.
The court had previously heard that Mr Allen used a prosthetic limb since his lower right leg was amputated as a result of a previous illness.
His car, a grey Mercedes GLA, had been supplied by a Motability car scheme and was parked in the forecourt at the time it was stolen.
The court heard Woodger had planned to steal tools and a vehicle and sell them on and get money to spend on drugs.
Mr Allen had been dozing or watching television in his ground floor flat in Peareswood Road when a man was caught on CCTV outside.
The man climbed over a low wall and got into a neighbouring unoccupied flat through a window, the prosecutor said.
The victim put on his prosthetic leg but left his other trainer on the sofa in his rush to confront the intruder in the communal hallway.
Mr Orchard said: “Within minutes, Marc Allen’s Mercedes was being stolen. His car keys had been taken. You can be sure he wouldn’t have handed them over voluntarily.”
Mr Allen was heard to shout “That’s my car. You aren’t taking my car”, as he stood on the driveway.
The car engine revved several times and Mr Allen may have suffered a “glancing blow” as the vehicle reversed quickly out of the...
[Short citation of 8% of the original article]