The Minister for Finance said his "heart fell" when he saw Conor McGregor in the Oval Office on St Patrick's Day.
Paschal Donohoe said the former MMA fighter does not represent Ireland and he believes that many people would have been "upset" when they saw him in the White House.
"My heart fell when I saw Conor McGregor in the Oval Office," he said.
"It fell as somebody who's been very proud to represent Ireland in America and elsewhere and it also fell as a man, because Conor McGregor does not represent this country.
"He doesn't represent the men of this country."
Mr Donohoe said he wanted to ensure people that the values of diversity and respect are dear to Ireland and to those who represent Ireland abroad and said that was not evident in the points Mr McGregor made in the White House.
"We really can't influence who President Trump wants to invite into the White House.
"That is a matter for President Trump and for those who work with him.
"But what we can influence is the message that we give out about ourselves as a country, and in particular, the case that those who are elected make about Ireland.
"And the case that we make is, like any other country in the world, we're far from perfect, but we're also a country that I believe has made great progress in the years and decades up to this point in terms of making the case for diversity, for openness and for respect and for treating each other with kindness and compassion.
"And that's the Ireland that I'll be making the case for."
He also rejected Mr McGregor's assertion that Dublin had become one of the most unsafe cities in the world
Responding to the figures that show Irish exports increased in a single month to the US by more than 80%, Mr Donohoe said he and others in the EU need to make the case with them that tariffs will increase prices and reduce growth.
"There are a number of other countries in the EU that also have a deficit performance and what we need to do now is to work with the US in terms of the issues they've raised.
"That has two different levels to us.
"The first one is making the case that the use of tariffs will take prices up, take growth down, and take the number of people employed within our economies down too.
"Secondly, identify different ways in which we can deal with how trade is structured between the US and the EU.
"In order to do that, we have to negotiate with the US. And I hope the next few weeks will allow us to do that."
Suggestions McGregor may seek election won't fly - Murphy
Meanwhile, suggestions that Mr McGregor is seeking to become a candidate in the presidential election later this year will not fly, People Before Profit TD Paul Murphy has said.
"I think they [Mr McGregor's suggested ambitions] will go very, very far in a social media site owned by Elon Musk, where a lot of people retweet him and boost him and so on, but I really don't think they'll go very far in terms of actually winning public support.
"He is not a beloved figure in Ireland for all the reasons people know, so I don't think that will get off the ground in reality, it might exist in Donald Trump's head and Elon Musk's head and their various promoters over there, but I don't think it'll fly," Deputy Murphy said.
Speaking at a press conference in Dublin, Mr Murphy also said that Taoiseach Micheál Martin's "quiet diplomacy" with US President Donald Trump last week is "no longer looking very smart" after Mr Trump's "abhorrent" and "really scandalous" White House meeting with Mr McGregor yesterday.
"I think it was really scandalous that Conor McGregor was set up to represent the Irish people on St Patrick's Day in the White House," he said.
"He is a man with abhorrent views on a whole range of issues," he said, adding that it is "abhorrent by the Trump administration to have promoted Conor McGregor in this way".
Mr Murphy said: "I do think that the so-called quiet diplomacy of Micheál Martin which was lauded by many commentators as being very smart no longer looks very smart, because the truth is while Trump is praising Conor McGregor, Micheál Martin while sitting in a room with him [Donald Trump] didn't say a single word to contradict him."
Referencing the meeting and the separate issue of Israeli attacks on Gaza overnight, Deputy Murphy said "clearly the very cowardly bootlicking approach of Micheál Martin is exposed for just that".
Last year, a jury in a civil case found Mr McGregor raped Nikita Hand in a hotel in Dublin in December 2018 and awarded her almost €250,000 in damages.
Tánaiste Simon Harris has said he was aware that there was a real sense of "disgust" in Ireland about Mr McGregor being in the White House yesterday.
Mr Harris reiterated that Mr McGregor does not speak for Ireland.
"He doesn't only not represent our values, he's actually the opposite of all of the values we're proud about in Ireland," Mr Harris said.
"He represents the very worst of toxic masculinity. I think we need to be very clear on that.
Mr Harris added that while Mr Trump can "have whoever he wants to visit him", he wished to be clear that Mr McGregor "wasn't there in any way speaking for us".
