Information Minister Redwan Hussein named the hijacker as 31-year-old Hailemedehin Abera Tagegn.
Hussein said Tagegn had been working with the national carrier for five years and had no criminal record.
"So far it is known that he was medically sane, until otherwise is proven through the investigation which is going on right now," the minister told reporters.
"So the intention, what forced him to hijack his own plane, still beggars belief . . . any political, social or economic reason would not make sense to hijack your plane and be a criminal," he said.
"We don't see any criminal record . . . and there was no reason for him to be prosecuted so there was no reason for him to flee," he added.
The minister said the passengers included 139 Italians, 11 Americans, 10 Ethiopians as well as nationals from Nigeria, Romania, France, Ireland, Germany and other countries.
None of the passengers were hurt, police said.
The Boeing 767-300 plane, which was originally headed to Rome from Addis Ababa, landed at Geneva airport at 6.02am on Monday.
When the pilot went to the toilet, the co-pilot seized the opportunity to lock himself in the cockpit and fly the plane to the Swiss airport, Geneva police said.
Upon landing he let himself out of a window with rope and surrendered to Geneva police, saying that he was seeking political asylum in Switzerland.
The man now faces charges in what marks the first plane hijacking in Switzerland since 1995 and the first ever involving a pilot.
Federal prosecutor Carlo Buletti is overseeing the case.