Dino Clark was jailed for 18 months over the heartless offence which took place on King Edward Street on September 20 last year.
Leeds Crown Court heard the 49-year-old victim was vulnerable as he had recently suffered a stroke.
Martin Robertshaw, prosecuting, said the man bought the electric bike for £850 to help him do his shopping and make social visits.
The prosecutor said the victim fell off the bike at 9.40pm as he rode through Leeds city centre.
Mr Robertshaw said: “The bike fell on top of him and because of his condition he was unable to get to his feet.
“While on the ground he was approached by a male and a female.
“The male was this defendant Clark.”
The court heard Clark picked up the bike and made off with it.
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He denied the offence when interviewed and claimed he was not the person on the CCTV footage.
Clark, of no fixed address, pleaded guilty to theft when he appeared before magistrates.
Mr Robertshaw said the bike has not been recovered.
Clark told a probation officer that he had sold the bike for financial gain.
At the time of the offence he was the subject of a community order for possessing a blade and criminal damage after he vandalised a car with a samurai sword.
He has previous convictions for offences of robbery, theft, violence and failing to comply with court orders.
Mr Reed said Clark’s offending was linked to drug use.
He added: “Spice has been his problem of late.”
Sentencing, Judge Simon Batiste said: “You are 29 and you have a terrible record.
“Whatever the position was, you knew and could tell he was in a vulnerable state.
“But you chose to ride away with this item.
“It is clear that it was an item that would have had considerable value to him given the medical condition that he had.”