Keane informed John Delaney and Martin O’Neill this morning, according to the Irish Independent.
The former Ireland captain had been offered the chance to take over from Neil Lennon at Celtic but turned it down to see out his commitment to the national team.
Keane is said to have been reviewing his options over the last few days before coming to his decision, and is now expected to fly out with the Ireland squad for their tour of United States and games against Costa Rica and Portugal.
The 42-year-old is then expected to join ITV’s World Cup punditry team in Brazil.