Mr Ansley said he put cable ties around the man's wrists to restrain him.
The man was struggling so Mr Ansley had to hit him on the head a few times to stun him, he said.
A group of passengers then tied the man to a row of chairs.
Mr Ansley asked the airline crew to check that the man was travelling alone, and went through his luggage.
"I was worried that this was a distraction for some other terrorism thing. I walked around the plane for the next four hours watching all the passengers to make sure nothing else was going to happen," he said.
When the flight arrived, police at Sydney airport took the man away and took the details of other passengers.
Mr Ansley posted a picture of a restrained man on his Facebook page and wrote: "This p***k tried to kill himself and all others onboard VN773 by jumping out emergency exit. Luckily three lads held him down while I stunned him with head shots then cable tied him."
He also wrote that passengers were later told the emergency door would not have opened at that altitude anyway.
The eventful flight meant Mr Ansley returned to work on Tuesday night with no sleep.
"It was horrible... I was really looking forward to a good sleep on the way back...I just wanted to get home to my son."
The Australian Federal police this afternoon confirmed it responded to a "request for assistance" at the Sydney International Airport yesterday.
The man involved had been been restrained by airline staff and passengers after allegedly attempting to open the exit door on the flight, a police spokesperson said.
"The man was escorted to St George Hospital for medical assessment."
He has been charged with endangering the safety of an aircraft and is due to appear at the Downing Centre court next month.
Staff are continuing to investigate the incident, the spokesperson said.
