Kelly told reporters in the White House briefing room that he counseled Trump on what to say to families of those killed on the battlefield. He also said "it stuns me" that Democratic Rep. Frederica Wilson listened in on a call, which was heard on speakerphone, between Trump and the widow of Sgt. La David T. Johnson, who was killed in an ambush in Niger.
Kelly confirmed Trump's claim that then President Barack Obama had not called his family when his son, 1st Lt. Robert M. Kelly, was killed in Afghanistan seven years ago. But Kelly said he did not fault the former president for that choice. Kelly added that he had recommended to Trump that he not make such calls.
"I said to him, 'Sir, there's nothing you can do to lighten the burden on these families,' " Kelly said.
Kelly's voice grew thin at points during an extraordinary and emotional briefing called as questions about Trump's handling of the Niger deaths and other military losses swamped the White House this week.
Kelly took the podium from White House press secretary Sarah Huckabee Sanders about two minutes into the daily briefing, and the room of reporters fell silent. He spoke for about 18 minutes, answering a few questions before departing, and ignoring others that were shouted at him as he left.
Kelly did not bring up - nor was he asked - how he felt about Trump thrusting his son's death into the political debate this week.
Trump had been asked Monday about his uncharacteristic silence following the deaths of four Special Forces soldiers on Oct. 4. Trump responded, in part, by saying that Obama and other predecessors had not called each family as he claimed he does. Trump invoked Kelly on Tuesday, saying "you could ask Gen. Kelly" whether Obama had called him when Robert died.
Kelly, one of several former military men Trump has brought into his administration, angrily called the actions of Wilson "selfish" and shocking.
The congresswoman spoke "in the long tradition of empty barrels making the most noise," Kelly said.
Wilson, a family friend of the fallen soldier, had criticized Trump's tone and choice of words in a call he made Tuesday to widow Myeshia Johnson.
In media interviews and on Twitter, Wilson said the president had been callous in telling Myeshia Johnson that her husband "must have known what he signed up for."
Trump denied saying that, and accused the lawmaker of trying to score political points.
Kelly, who was listening in on the call, did not dispute or directly address the substance of Trump's remarks to Johnson, but said the president had done a hard job well.
"He elected to make phone calls in the case of four young men who were lost in Niger. . . . Then he said, 'How do you make these calls? If you're not in the family, if you've never worn a uniform, you've been in combat, you can't even imagine how to make that call. But he very bravely does make those calls."
Trump had said Wednesday that the lawmaker's account was "totally fabricated."
"John Kelly's trying to keep his job," Wilson told Politico on Thursday. "He will say anything. There were other people who heard what I heard."
Kelly, who became the highest-ranking military official to lose a child in Iraq or Afghanistan, watched both his sons follow him into the Marine Corps. When Robert died after stepping on a land mine in southern Afghanistan in 2010, Kelly and his sons had participated in 11 combat tours in Iraq and Afghanistan combined.
Kelly noted Thursday that his surviving son is currently serving in Iraq. He has been private about Robert's death, even though both his and his sons' military service clearly informs his thinking on White House foreign policy and national security decisions, several White House officials said.
"In my case, hours after my son was killed, his friends were calling us from Afghanistan, telling us what a great guy he was. Those are the only phones calls that really matter," Kelly said.
"If you elect to call a family like this - and it's about the most difficult thing you could imagine - there's no perfect way to make that phone call."
Kelly began his remarks with a stark and meticulous explanation of what happens to fallen military personnel overseas.
"Their buddies wrap them up in whatever passes as a shroud, puts them on a helicopter as a routine and sends them home," he said. Their first stop along the way is when they're packed in ice, typically at the airhead, and then they're flown to,usually, Europe, where they're then packed in ice again and flown to Dover Air Force Base."
"Where Dover takes care of the remains, embalms them, meticulously dresses them in their uniform with the - with the medals that they've earned, the emblems of their service, and then puts them on another airplane linked up with a casualty officer escort that takes them home," he said.
He also walked through the process of what happens when "a casualty officer" visits the home of a fallen soldier.
"The casualty officer proceeds to break the heart of a family member and stays with that family until - well, for a long, long time," Kelly said. "Even after the internment. So that's what happens. Who are these young men and women? They are the best one percent this country produces."
Kelly said he had taken a 90-mionute walk among the graves at Arlington National Cemetery to clear his head Wednesday morning, when Wilson's claims and Trump's rebuttal dominated news coverage.
Kelly said little about the circumstances of the soldiers' deaths in Niger, an African nation fighting an Islamist insurgency.
Defense Secretary Jim Mattis, asked Thursday at the Pentagon if he was angry that Gold Star families have been dragged into a political dispute, kept his response succinct.
"We honor our fallen in America, and that's all I'll say."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)