Firefighters from the Manutuke volunteer fire brigade and the city managed to get him out from underneath the tractor.
"While the St John ambulance officers were administering first aid we set up high pressure air bags and spreaders under the tractor," said Senior Station Officer Mike Milne.
"We were able to take the weight of the tractor off his legs and then we slid him out from underneath."
Mr Milne said the young man "handled the situation very well".
He was taken to the emergency department at Gisborne Hospital for initial care, then flown to Waikato Hospital.
"He has been admitted to a general ward," a Waikato spokeswoman said today. "He is in a stable condition."