Sheffield councillor Maroof Raouf shared the video on Twitter and demanded action.
The video, which appears to have been filmed on school premises, shows a boy being attacked by a group of youths.
He is pushed to the ground before one jumps on him and punches him repeatedly in the head, and another starts to kick him.
A man in sports kit then intervenes and pushes the first two attackers away before other runs up to the boy on the ground and kicks him.
The man in the sports gear – allegedly a member of staff – continues to try and keep the attackers away from the boy on the ground, while the attackers attempt to fight the man off and get back to hitting the boy.
Cllr Raouf said: “Parents of children in the academy have contacted me tonight to say racism is rampant in your school, what safeguards have you in place to protect ALL children at your school?”
He then asked South Yorkshire Police if the force is going to arrest the attackers.
A witness said: “I understand the boy is currently in hospital receiving care for his injuries. This boy could have been killed. As a concerned member of the community I hope you can look into this.”