In his first comments addressing the speech controversy, Trump argued early on Wednesday that the fuss could in fact be a plus for his campaign.
Trump aide Meredith McIver acknowledged Wednesday that she had included some of Michelle Obama's convention speech in her research notes and then included those notes in the speech. Over the phone, she read me some passages from Mrs. Obama's speech as examples. But McIver wrote the phrasing down in a draft that ultimately made its way into the final speech Melania delivered on Monday night. This was my mistake, and I feel bad for the chaos I have caused Melania and the Trumps, as well as to Mrs. Obama. "No harm was meant", wrote McIver.
"I personally admire the way Mr Trump has handled this situation and I am grateful for his understanding".
McIver said Trump and his family rejected an offer from her to resign after the speech controversy broke.
There are few details about McIver, who was described as an in-house writer for the Trump Organization where she started in 2001.
For two days, the Trump campaign tried to brush aside any talk of plagiarism, calling the criticism absurd.
Meredith McIver has been working for Donald Trump since 2011.
Mr Trump also took a swipe at the media, which he has repeatedly alleged is biased against him and favours Democratic presumptive presidential nominee Hillary Clinton, who herself has recently been mired in an email scandal. She wrote that she asked to put out the statement because she "did not like seeing the way this was distracting from Mr. Trump's historic campaign for president and Melania's attractive message and presentation".
"I apologize for the confusion and hysteria my mistake has caused", she added.
"Good news is Melania's speech got more publicity than any in the history of politics especially if you believe that all press is good press", Trump tweeted. One referred to what Mrs. Trump called values impressed upon her by her parents.
There were similar overlaps in a passage dealing with conveying to children that there is no limit to what they can achieve.
Mrs. Trump's address was otherwise distinct from the speech that Mrs. Obama gave when her husband was being nominated for president.