The JFA confirmed the decision to Reuters via telephone following a council meeting in Tokyo. The move comes after Akira Nishino, who led Japan to the last 16 at the World Cup, stepped down from the role.
It is unclear whether Moriyasu, who was part of Nishino's staff in Russia, would also remain in charge of the Olympic team for the 2020 Games in Tokyo.
Moriyasu's first task will be preparing Japan for the 2019 AFC Asian Cup in January. Japan, who have won the competition a record four times, have been drawn in Group F alongside Uzbekistan, Oman and Turkmenistan.
The 49-year-old played 35 times for Japan during the 1990s, including in the 'Agony of Doha' match when they failed to qualify for the 1994 World Cup following a last-minute equaliser by Iraq.
As a coach, Moriyasu guided Sanfreece Hiroshima to three J.League titles between 2012 and 2015 before resigning in 2017 following a run of poor results.
(Reporting by Jack Tarrant; Editing by Peter Rutherford)
