The 21-year-old resident called police at 1am on Sunday morning to report two men who he said had smashed a window at his house in Koorawatha, about 300 kilometres west of Sydney.
He then armed himself with a golf club and attacked one of the alleged intruders, a 42-year-old man, leaving him with serious injuries to his face.
The older man was then restrained by the homeowner who waited for police to arrive.
Officers and paramedics arrived at the scene.
“A 42-year-old man was taken to Cowra Hospital in a serious but stable condition before being airlifted to Liverpool District Hospital,” a statement from police said.
The younger man was taken to the Young Police Station where he is assisting officers with the investigation.
Police are trying to find the second alleged intruder.
Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or visit nsw.crimestoppers.com.au.