Barry Rogerson attacked the animal outside St James' Park after the game between Newcastle and Sunderland on 14 April 2013.
The unemployed 45-year-old, of Morpeth, Northumberland, pleaded guilty to a charge of violent disorder and was jailed at Newcastle Crown Court on Thursday.
Rogerson was also ordered to serve a six year football banning order.
The case was heard three days before the teams face each other at the Stadium of Light on Sunday.
Robert Adams, mitigating for Rogerson, told the court: "Mr Rogerson was a man of good character.
"He is 45-years-of-age and he, perhaps more than any other, has had the humiliation of almost constant press coverage about his involvement.
"He is extremely embarrassed and ashamed of what happened. It has been difficult for him but also for his family and friends.
"He has a very good work record of 22 years, it is only illness that stops him from working. He has never bothered the police before in any way and he has never appeared in any court.
"He lives on disability allowance and his wife is in employment.
"He is therefore a man of difficulties. He is not somebody who has ever supported or encouraged this type of behaviour.
"There is no question he had a particularly large amount to drink on this day.
"He had gone to watch the match, he was with a group of friends. Most of them were completely unaware what took place until afterwards.
"He was not involved in any trouble before the start of the match. He appears afterwards to have taken up a position at an early stage. When there was a line of Newcastle supporters facing the police he was joining in with the jeering that was taking part at that stage.
"Sadly for him he maintained his position during the two sieges.
"He did not punch any human, officer or Sunderland supporter in any way. No missiles or other weapon was thrown by the defendant.
"He has no previous convictions of any sort. It is not the case that he was involved in other acts of violence around the city centre.
"His wife has told him he is not going to another football match ever."
He added: "Mr Rogerson has acted completely out if character while under the influence of drink."
Unemployed Rogerson apologised for his behaviour shortly after he was filmed hitting the horse.
Following the game there was wide-spread disorder in Newcastle city centre as rival fans clashed.
Rogerson, a former planning controller who has been unemployed for eight years, said: "I never had any intention of getting involved in any riots, I was going to the next bar and I was in the middle of it all.
"Someone let a fire-cracker off and the horse was charging towards me.
"I just reacted stupidly, I realised what I had done once I was on the floor with police.
"The officers tripped me up, which is why I had blood on my nose, it was all a blur.
"My friend came across and wiped the blood off my nose. I didn't start out to do it.
"I was trying to get the horse away. I definitely regret it, it is my first offence and I am 45-years-old."
When asked why he was wearing a scarf around his face the dad-of-one said: "It looks bad, but my filling fell out and it was cold on Sunday.
"I wasn't drunk, I had two pints before the match and a bottle at half time. The police were fine. They said thank-you for being honest and polite.
"I am sorry for hitting the horse, and I am sorry for the whole incident. I have embarrassed myself and my family."
Don't forget you can tune in for Gus Poyet's first home game as Sunderland manager against Newcastle United on Sunday from 12.30pm