He wept at Stockport magistrates' court this week as he admitted assault by beating but claimed the shooting was a "momentary lapse of judgment", saying he was going through an acrimonious divorce at the time and was not sleeping well.
He was ordered to complete 200 hours of unpaid work and pay the boy $241 compensation.
The incident happened in a room full of other children and adults on January 14 this year.
Miss Eileen Rogers, prosecuting, said: "He was operating an air rifle when one of the students asked the teacher what it would be like to be shot by it.
"He replied it would "bloody hurt", to which the young pupil responded "shoot me", running around the hall and repeating the phrase a number of times. He pointed the airsoft gun at him and fired it one or two times and one or more of the plastic bullets hit the young pupil and caused some injuries.
"He immediately went to check he was ok and apologised to him and at that point the pupil left the room.
"The boy did have some injuries, as a result he was extremely upset. Mr Gitlin is greatly remorseful and has no previous convictions."
In mitigation, defence barrister Rob Lassey said Mr Gitlin, from Prestbury, Cheshire, had fully admitted responsibility for the offence and has apologised in writing to the boy's parents "on a number of occasions". He added: "He resigned from his position at the school a couple of weeks after this incident. His teaching career is almost over - after 30 years" experience.
"At the time he was going through a very acrimonious divorce from his wife of 17 years. He was under enormous strain both emotionally and financially."
The barrister said Mr Gitlin will also have to give up other activities in which he was involved, including the Duke of Edinburgh award and volunteering with St John Ambulance.
Magistrates told the former teacher: "You were in a position of trust supervising this 11-year-old child in an environment where other children were present.'It is clear that it was a stupid mistake and a momentary lapse of judgment and it has tremendous consequences for you."