Sheffield Wednesday striker Gary Madine, 23, who has a previous conviction for knocking a man out in a Carlisle pub, punched Wednesday fan Daniel Beresford in the Paris Bar in Sheffield city centre in February last year, breaking his nose.
Four weeks later, he punched bricklayer and Sheffield United fan Reece Hall in the city's Viper Room club, shattering his cheekbone.
He was jailed at Leeds Crown Court after being found guilty by a jury following a week-long trial last month.
Judge Rodney Jameson QC sentenced the footballer, who will now automatically be sacked by his club, to six months for the ABH on Mr Beresford and 12 months for the offence of GBH against Mr Hall, whose cheekbone was shattered in the attack.
Alison Dorrell, defending Madine - known by some Wednesday fans as Goal Machine - said he had thrown away his talent due to "drink, childish behaviour and a temper problem".
She said: "He is not an asset to his club any more" and said he would struggle to re-start his career after serving a prison sentence.
Judge Jameson said the assaults occurred when the footballer "lashed out" when drunk with "little, if any, thought for the consequences".
He said: "When sober there is no reason to suppose that you would misbehave but I have to sentence you for serious offences which reflect the other side of your character.
"The side which comes out when you are in drink, which causes unprovoked violence causing serious injuries to innocent members of the public."
The judge said Madine had chosen not to "suppress" that side of his character.
However, Judge Jameson said other professional footballers had rebuilt careers after serving time in jail and there was no reason why he could not.
Madine, who used to earn £5,000 a week, was also told that he would have to pay £1,500 in compensation to Mr Beresford and £4,200 court costs.
Ms Dorrell said believed this would be difficult for the defendant who has not been paid by the club since he was convicted last month.
She said was he struggling to pay a mortgage on the house where his family lived.
Judge Jameson told the defence barrister that he would vary the compensation and costs if evidence could be provided that proved the defendant's difficult financial position.
He said he was conscious of the position of the footballer's family but said: "Much of the £5,000 a week went on high living."
The court heard how Madine has been training with Carlisle United and had undergone an anger management course in an attempt to address his temper issues.
Ms Dorrell said that Dave Jones, the Sheffield Wednesday manager, who was "not an easy man to impress" said of Madine that "his pride has seemed to give way to some common sense".
Last month the jury cleared Madine of the more serious charge of causing Mr Beresford grievous bodily harm.
But they unanimously found him guilty of actual bodily harm.
The footballer was also found not guilty of causing Mr Hall grievous bodily harm with intent but the jury found him guilty of the lesser offence of grievous bodily harm by a majority of 10 to 2.
He attacked Mr Hall on March 11, 2012.
Prosecutors told the jury that Madine turned into "an arrogant, violent thug" when drunk.
Mr Beresford told the court how he did not know why he was punched.
The court heard that Madine stared at him in the Paris Bar and when the keen Owls fan asked him why, the player walked over and punched him on the nose.
Mr Beresford, who is 5ft 9in, was knocked to the floor, banged his head and was knocked out for between two and five minutes in the 1am attack, the court heard.
Madine claimed he was acting in self-defence after a drink was thrown over him and was worried he was going to be hit with a glass or a bottle.
But Judge Jameson said this evidence showed that this was "a lie".
Mr Hall was attacked after Madine started a conversation with him in the Viper Room toilets, asking him "Wednesday or United?".
Mr Hall picked out Madine for police in the bar. The footballer was arrested and admitted abusing officers who put him in a van saying "I'll have you all" and then swearing at a custody sergeant.
Madine, who said he is 6ft 3in and weighs 14st, is originally from Gateshead and told the court he supports Newcastle United.
A statement on Sheffield Wednesday's official Twitter site said: "Following the sentencing today at Leeds Crown Court, SWFC have no comment at this time and will issue a statement in due course."