He did not speak to his father for more than a year after his rocky divorce from Ivana Trump.
After the uproar of the Russian email controversy, the author of a Donald Trump tell-all book says Donald Jr. has always been the problem child.
Read: Meet the Publicist Behind Donald Trump Jr.'s Email Controversy
“Donald Trump has often been asked, 'Which of your kids gave you most trouble, which was most problematic?' and his answer is always Donald Trump Jr.,” Washington Post senior editor Marc Fisher, the author of Trump Revealed, told Inside Edition.
His son was a key figure in Trump's campaign, but his relationship with his dad has been rocky in the past, especially after Donald Sr. divorced the mother of his three oldest children — Ivana — in 1992.
“For more than a year after Donald Trump and Ivana separated, Donald Jr. did not talk to his father," Fisher told Inside Edition. "He was that angry, that alienated from his father, that betrayed and this period of rebellion went on for some years."
Father and son did eventually reconcile. The president even introduced him to his wife, former model Vanessa Haydon. She and Trump Jr. married in 2005 and have five children.
Meanwhile, questions have been raised about what President Trump knew about the explosive emails that promised incriminating info about Hillary Clinton.
A campaign speech was delivered on June 7, 2016, four days after Donald Trump Jr. was contacted by publicist Rob Goldstone, who said he had dirt on Clinton.
Trump, with Ivanka and Melania by his side, promised during the speech that he had some big news in the coming days on his opponent.
“I am going to give a major speech on probably Monday of next week, and we’re going to be discussing all of the things that have taken place with the Clintons,” Trump said. “I think you’re going to find it very informative and very, very interesting. I wonder if the press will want to attend. Who knows?”
Two days later, Trump Jr. was to meet with Russian lawyer Natalia Veselnitskaya and Goldstone about the alleged Clinton intel.
The New York Times obtained a screenshot of Goldstone’s Facebook page, showing that he checked into Trump Tower on June 9, 2016, the day of the gathering, with the status: “Preparing for meeting.”
Trump Jr. appeared on Hannity Tuesday night to defend himself and insist that his father knew nothing of the rendezvous.
"I didn't know if there was any credibility," Trump Jr. said. "I didn't know if there was anything behind it, I can't vouch for the information. Someone sent me an email. I can't help what someone sends me. I read it, I responded accordingly."
Trump Jr. denied knowing Veselnitskaya prior to the meeting. The attorney told NBC News Tuesday morning that she did not have "any damaging or sensitive information about Hillary Clinton.”
She added: “It was never my intention to have that."
The president took to Twitter Wednesday morning to defend his son and say everything is fine in Washington.
Read: Chelsea Clinton Lashes Out at President Trump Amid Ivanka Stand-In Uproar
“My son Donald did a good job last night. He was open, transparent and innocent,” he tweeted. “This is the greatest Witch Hunt in political history. Sad!”
My son Donald did a good job last night. He was open, transparent and innocent. This is the greatest Witch Hunt in political history. Sad!
— Donald J. Trump (@realDonaldTrump) July 12, 2017
“The W.H. is functioning perfectly, focused on HealthCare, Tax Cuts/Reform & many other things. I have very little time for watching T.V,” he added.
The W.H. is functioning perfectly, focused on HealthCare, Tax Cuts/Reform & many other things. I have very little time for watching T.V.
— Donald J. Trump (@realDonaldTrump) July 12, 2017
Trump Jr. admitted to Hannity that he may have made a mistake.
“In retrospect, I know more now, but hindsight’s always 20/20,” he said.
Watch: Artist Creates Image of Vladimir Putin in Wheat Field Ahead of G20 Summit
