Medal-winning cyclist Simon Richardson was training for the London games near his home in Bridgend, south Wales, when 61-year-old Edward Adams knocked the sportsman over in his van before driving off.
Mr Richardson suffered a fractured spine, broken pelvis, collapsed lung and perforated bowel.
After the crash Adams, an alcoholic, then rushed back home to hide his vehicle before pouring himself a glass of whisky, in a bid to try to disguise the fact he had been drinking before the collision, Cardiff Crown Court was told.
Judge Daniel Williams said Adams had shown limited empathy for his victim, and none of the courage and dignity displayed by Mr Richardson.
He said: "You first got into the car at 8.45am that morning and when you were breathalysed just after midday you were more than twice the legal drink drive limit.
"Mr Richardson was clearly visible, cycling close to the kerb and wearing bright clothing.
"Your claims that you were affected by sneezing and sunlight were wholly untrue.
"Your reaction to the accident and its aftermath could not be in greater contrast with the man that you had left injured.
"You took the opportunity to leave the scene knowing you had caused the accident."
Mr Richardson, 44, who won two gold medals and a silver in 2008, was training for the London Games on the A48 on a road known locally as Crack Hill in August last year.
Cardiff Crown Court heard he was thrown 26 metres into the air after Adams' van hit him from behind.
He stopped briefly, but drove off after he noticed another motorist had stopped to offer him assistance.
Adams then attempted to hide his Peugeot van at his farm.
It was eventually located by a police helicopter, and was found with damage to a wing and windscreen.
Adams, when interviewed by police, said he had been drinking the night before and had drunk his first whisky at 6am when he woke up.
He admitted drink-driving and failing to stop, but denied a charge of dangerous driving.
Judge Williams described Adams' version of events during his trial as "instinctive lies" and said the sentence he imposed reflected the serious harm and injury Mr Richardson had been caused.
Adams was given a 15 month prison sentence for dangerous driving, and an extra three months jail for failing to stop.
A three month sentence for driving with excess alcohol will run concurrently.
Adams will also be disqualified from driving for five years.
Following the court's verdict, Mr Richardson said he faced an uncertain future.
The father-of-two said: "I still have another operation to go through, which if it is unsuccessful could leave me permanently paralysed.
"It's also been difficult to miss out on taking part in the London Paralympics. But I am a strong person, and plan to keep on fighting.
"As for the court's verdict, I am happy in a way with the sentence.
"I would have been happy whatever sentence he got - even if he walked free.
"At the end of the day, it was just an accident and he did not deliberately set out to knock me down.
"But it is important that a precedent has been set; that not only should a person be charged with excess alcohol but it also qualifies as dangerous driving.
"I hope this incident shows the need for drivers to be more aware of cyclists on the road."