Leeds Crown Court heard wheelchair user Michael Long, 29, verbally abused Shaun Walsh during the incident outside McDonald’s on Briggate.
He used his wheelchair footrest to hit Mr Walsh on the head and elbow at around 10am on May 6.
Mr Walsh suffered a broken bone in his right elbow and cuts to his head.
Father-of-two Long, of no fixed abode, admitted grievous bodily harm and possessing cannabis.
The court was told he was jailed for six years in August last year for robbery.
Judge Tom Bayliss QC jailed him for an additional six months for the attack on Mr Walsh.
Prosector, Susan Evans, said the attack happened after Long, who the court heard was often begging in Leeds, had asked Mr Walsh for £1 and he refused.
Miss Evans said Long was jailed for six years last August for a 2015 street robbery.
The court heard Long was on bail for that robbery when he attacked Mr Walsh.
Mitigating, Nigel Jamieson, said his client, who served in the army for two years from the age of 16, has suffered long-term mental health and drink and drug problems.
Mr Jamieson said: “He believes the complainant had made some derogatory comments about his own children and that’s what caused him to lose his temper, but there is no excuse and he apologises for that.”
Jailing Long for six months, Judge Bayliss, said: “You hit him twice using part of your wheelchair as a weapon and caused quite a serious injury, a fracture to his elbow.”