Speaking at a press conference in Paris, the President said he had done nothing wrong and anyone in the same situation would have done the same.
Trump was responding to a reporter who quoted his nominee for FBI Director, Christopher Wray, who said yesterday that anyone in an election campaign team who received such an email should have alerted the FBI.
Trump said: "My son is a wonderful young man and he took a meeting with a Russian lawyer, not a [Russian] government lawyer but a Russian lawyer.
"It was a short meeting. It was a meeting that went very, very fast, two of the people in the room, one left almost immediately and the other, I guess, wasn't very focused on the meeting."
"As I see it they talked about adoption and some things, adoption wasn't even part of the campaign. But nothing happened from the meeting, zero happened and honestly, I think the press made a very big deal over something that really, a lot of people would do."
But there is one glaring hole in the argument - Don Jr went to the meeting expecting to meet a Russian government official who had damaging information on Hillary Clinton that was part of a concerted Russian government attempt to influence the 2016 election.
In the emails arranging the meeting published by Trump's son, a passage reads:
The Crown prosecutor of Russia met with his father Aras this morning and in their meeting offered to provide the Trump campaign with some of the official documents and information that would incriminate Hillary and her dealings with Russia and would be very useful to your father.
This is obviously very high level and sensitive information but is part of Russia and it's government's support for Mr Trump - helped along by Aras and Emin.
What do you think is the best way to handle this information and would you like to speak to Emin about it directly?
Don Jr changed his defence of the meeting multiple times over last weekend as The New York Times steadily published details.
He initially argued it was a "short introductory meeting" focused on the disbanded program that had allowed American adoptions of Russian children, without mentioning anything about the Russian support for his father.
He posted the full emails only after they were obtained by The New York Times who told him they were writing an article on them.
At today's press conference, held jointly with President Macron of France, Trump tried to pass the meeting off as simply "opposition research" and, perhaps unintentionally, implied that when offered information it's standard practice to accept it.
He said: "I do think from a practical standpoint, most people would have taken that meeting. It's called 'opposition research'.
"I've only been in politics two years and I've had many people call up and say 'oh gee, we've got information on this factor or this person', frankly Hillary - it's very standard in politics, it's not the nicest business in the world but it's standard where they have the information and you take the information."
Trump also attempted to shift the blame, saying: "Now the lawyer that went to the meeting, I see that she was in the halls of Congress all summer and somebody said that her visa - or her passport - to come into the country was approved by Attorney General Lynch.
"Now maybe that's wrong, I just heard that a little while ago but I was surprised to hear that, but she was here because of Lynch."
Trump also appeared to quell any repeats of the question from reporters by choosing a foreign correspondent when it was his turn to pick for a second time, rather than an American journalist as would have been normal.