Oliver Clarkson, aged 31, of Burgoyne Road, Walkley, was serving time at Doncaster prison for criminal damage offences when he attacked a guard in September 2016.
Surgery for man hit in face with champagne bottle in Sheffield nightclubHe was locked up again on Friday after pleading guilty to assault.
New Sheffield police chief issues warning to gangsDetective Constable Emma Taylorson, from South Yorkshire's Prison Investigation Team, said: "Clarkson was serving a 28-day sentence for criminal damage offences in September 2016 when he assaulted a prison officer in an unprovoked attack.
"The officer was left unconscious as a result of Clarkson’s violence and I am pleased that he accepted responsibility and has been sent back to prison for his crime.
"We work closely with the prison service and crimes of violence against their staff are completely unacceptable."
SHOCKING courtroom brawl breaks out after Sheffield cousins are found guilty of shooting man in handJerry Spencer, Serco’s Contract Director at HMP Doncaster, said: "We take a zero tolerance approach to any and all violence in our prison and we are pleased at the court’s decision."