Phil Hogan has been chosen as the next EU trade commissioner.
He will serve in the new European Commission for five years under Ursula von der Leyen.
Mr Hogan is currently the outgoing commissioner for agriculture.
Announcing the move on Tuesday in Brussels, Ms von der Leyen said he "will bring his experience to the new commission in the trade portfolio."
This also puts Mr Hogan front and centre for negotiating on any post-Brexit trade deal between the EU and UK.
President-elect von der Leyen said: "This team will shape the European way: we will take bold action against climate change, build our partnership with the United States, define our relations with a more self-assertive China and be a reliable neighbour, for example to Africa.
"This team will have to stand up for our values and world-class standards.
"I want a commission that is led with determination, that is clearly focused on the issues at hand and that provides answers.
"I want it to be a well-balanced, agile and modern commission.
"This team will now have to gain the parliament's confidence.
"My commission will be a geopolitical commission committed to sustainable policies.
"And I want the European Union to be the guardian of multilateralism. Because we know that we are stronger by doing together what we cannot do alone."
The new commission will have eight vice-presidents - including the High-Representative for Foreign Policy and Security Policy, Josep Borrell.
Three executive vice-presidents will have a double function: they will be both vice-president responsible for one of three core topics of the president-elect's agenda and commissioners.
Executive vice-president Frans Timmermans will coordinate work on the European Green Deal.
He will also manage climate action policy, supported by the directorate-general for climate action.
On his appointment, Mr Hogan said: "I am very pleased to have been nominated by President-elect von der Leyen to the position as commissioner-designate for trade in the next European Commission.
"This is undoubtedly one of the most important economic portfolios in the College of Commissioners and the appointment comes at a very important time for the European Union and for Ireland.
"International trade is the lifeline of the EU economy and its economic importance is illustrated by the fact that one in every seven jobs in the EU is supported by the export of goods and services.
"Trade is a political priority for the European Commission and one with which I have been very closely involved during my term as commissioner for agriculture & rural development."
"Ireland is a small, open, export-orientated economy, which has been a very significant beneficiary of EU trade policy and the growth of exports over many years.
"Today, it is estimated that that exports to countries outside the EU support around 650,000 jobs in Ireland, particularly in such sectors as agri-food, pharma, medical devices, med-tech and financial services.
"I am very much looking forward to starting in this exciting and challenging portfolio and to supporting President-elect von der Leyen in her pursuit of a 'strong, open and fair trade agenda', through which Europe's role as a global leader can be strengthened."
The EU is the largest exporter of agri-food products in the world, with exports of €138bn last year.
The European Parliament now has to approve the commission.
This is preceded by hearings of the commissioners-designate in the relevant parliamentary committees.
Once the European Parliament has given its consent, the European Council formally appoints the commission.
Mr Hogan served as Ireland's environment minister from 2011 to 2014.