Children at Vale First and Middle School in Worthing, West Sussex, were excited to be entertaining Mayor Noël Atkins and his wife Helena at their production of Bugsy Malone.
However, the budding actors confidence was crushed when their guests of honour dozed off within minutes of curtains up on their rendition of the gangster story.
Some of the youngsters, aged 11, were left sobbing during the interval, believing that the couples lethargy was a reflection of their performance.
Parents condemned Mr Atkinss behaviour as appalling and demanded that he apologise.
Ashley Knowlson, 11, who played a tramp in the chorus, said: "I couldn't believe he fell asleep. Some of the girls were very upset.
"It was cheeky of him. We worked really hard and I loved being in the show."
His mother, Tina Knowlson, 42, who was in the audience, said: "The kids all worked really hard and rehearsed loads and were really proud of it.
"It was a big night for them to do it in front of the mayor - he was the VIP. The least he and his wife could have done was to stay awake for the performance. It's a shame he ruined what could have been a special night for them."
Another parent, who asked not to be named, said: "The couple were the guests of honour but within 20 minutes they had both fallen asleep.
"It's just disappointing for the children. Some of them were crying during the interval and asked what they were doing wrong.
"They thought the mayor was bored because their performance wasn't good enough."
The production was laid on by Year 7 pupils at the school which caters for more than 600 children aged between four and 11, who had spent weeks rehearsing for the big night.
The council confirmed that Mr Atkins, 66, had nodded off during the show, but said it had been his final official engagement after a very tough day.
A spokeswoman said: He dozed off during the performance but it wasnt as if he was snoring.
He has had such a tough time lately. He is the councils business champion and had attended several meetings during the day, doing a lot of very intensive work.
He barely had enough time to get home, change and get to the musical on time and was extremely tired. He just shut his eyes for a few minutes.
Apologising yesterday, Mr Atkins, a father of five, blamed his wife's medication tablets and his heavy cold for their snooze.
He said: "I would like to apologise if I have upset any of the children.
"A reviving cup of coffee did work wonders, and we were pleased to meet and chat with the children during the interval and enjoy their performance of Bugsy."
Despite getting his free bus pass last year, Mayor Atkins is normally better known in his home town for his energetic approach to local politics.
He threw himself into his first engagement after his appointment last May by "crowd surfing" over a 14,000-strong audience at a church festival
Wearing his official chain, he was carried aloft for two minutes by the cheering crowd in scenes that became an instant hit on YouTube, the video sharing website.
He said at the time: "It was a great sensation though I was a little concerned that I might lose my trousers."
In August last year, Mr Atkins made a 12,000ft parachute jump to cure his fear of heights before landing in a heap of cow dung near Headcorn, Kent.
