The Italian, who is currently in charge of Austrian champions Red Bull Salzburg, confirmed he would leave the club at the end of the season and take over as Ireland boss at the start of June.
"Leaving the title as a farewell present to my Bulls is now my number one aim," the 68-year-old said.
Salzburg confirmed Trapattoni's departure in a statement on its web site.
"Giovanni Trapattoni has made a decision on his future just before the 2007/2008 Bundesliga resumes after the winter break: The 'Mister' is to take on the job of Irish national team manager after the end of the season - for a two-year contract," the statement read.
"Leaving the title as a farewell present to my Bulls is now my number one aim."
Details of Trapattoni's financial package were agreed at a meeting between the coach and a Football Association of Ireland (FAI) delegation led by John Delaney, chief executive, in Milan on Tuesday evening.
The 10-member board of the FAI was due to meet later Wednesday when the appointment was to be officially ratified.
Bringing the backroom
The former Juventus, AC Milan and Inter Milan coach, who has won league titles in four countries (Austria, Germany and Portugal as well as his native Italy) is expected to bring his backroom staff of Claudio Gentile and Fausto Rossi with him into the post.
Ireland legend Liam Brady, who won two Serie A titles under Trapattoni at Juventus and is now in charge of Arsenal's youth development, is also expected to have a role though its precise nature is unclear.
Brady's understanding of the Irish sports mentality, the respect he commands in the Irish game, and being able to speak Italian are considered important given Trapattoni's limited English.
Trappattoni will seek to lead Ireland to their first major finals since the 2002 World Cup in Japan and South Korea.
He was not expected to be present at the rubber-stamping of his appointment in Dublin on Wednesday afternoon.