A native of Kusu District, Ōita, he attended Waseda University as both undergraduate and graduate. He was elected: in 1971 as the Mayor of the town of Kusu, Ōita, elected in 1977 to the House of Councilors and elected in 1983 to the House of Representatives for his inaugural term; Eto has been returned to office eight times for the 2nd District for Oita Prefecture. In 1995, he was the Director General of the Japan Defense Agency and in 2001, he was Senior Vice Minister for Foreign Affairs. In 2002, he was elected as a head of the LDP's Oita Prefecture chapter and in 2009, he was elected as Vice-Speaker for the House of Representatives.
Etō was a leader in the movement to make Mountain Day a national holiday.[3]