The Republican nominee, speaking in Des Moines, Iowa, accused Clinton of being "unbalanced" and "unstable," called her a "dangerous" and "pathological" liar and warned voters in this swing state that a Clinton presidency would lead to "the destruction of this country from within."
After knocking himself off message repeatedly in recent weeks, stoking one controversy after the next, Trump, reading at times from prepared remarks on his podium, latched onto voters' concerns about Clinton's trustworthiness and honesty, and sought to amplify the controversies that have beset the Democrat's campaign.
"Unstable Hillary Clinton, lacks the judgment, temperament and moral character to lead this country -- and I believe that so strongly," Trump told supporters as he accused Clinton of supporting policies that he said could damage US national security. "She's really pretty close to unhinged, and you've seen, you've seen it a couple times. The people in the background know it, the people who know her know it and she's like an unbalanced person."
Repeatedly during his rally in Des Moines, Trump returned to the topic of Clinton's character, intertwining those attacks with others on her policy positions and record as secretary of state.
While he did not entirely abandon his signature style of jumping from one topic to the next -- including a tangent during which he explained his controversial comment about a crying baby
at a recent rally -- Trump spent more of his time on the stump than at any rally in recent weeks attacking Clinton.
"The legacy of Hillary Clinton: death, destruction, chaos and weakness," Trump said. "She's weak. She's a weak person. I know her. She's a weak person."
Trump's campaign later released a web video highlighting the controversy over Clinton's use of a private email server while leading the State Department, writing on Facebook
that there is "no doubt" that Clinton "is a pathological liar."
Trump pressed forward with his attacks on Clinton's character during his next stop Friday night in Green Bay, Wisconsin.
"In one way she's a monster," Trump said. "In another way she's a weak person. She's actually not strong enough to be president."
Trump's attacks on Clinton's character found their mark with his supporters in Des Moines, who broke out in chants of "Lock her up! Lock her up!" to which Trump offered a smile, a thumbs-up and a "thank you" -- just over a week after he rejected those chants as a "shame," before later saying he agreed with the chants.
Several Trump supporters responded more aggressively to Trump's biting excoriation of Clinton's character.
"Traitor," shouted one person in the crowd.
"Kill her," added another.
A message left with the Trump campaign Friday afternoon was not immediately returned.
Trump's character also questioned
But Trump's assault on Clinton's character also came as he himself faced stinging criticism from top US officials, including a damning editorial
on Friday in which the former acting head of the CIA, Michael Morell, a well-respected and non-partisan figure, endorsed Clinton and warned that Trump "is not only unqualified for the job, but he may well pose a threat to our national security."
"The character traits he has exhibited during the primary season suggest he would be a poor, even dangerous, commander in chief," Morell wrote, pointing to Trump's "obvious need for self-aggrandizement, his overreaction to perceived slights" and "his routine carelessness with the facts."
It's a similar line of attack that Trump has faced from Clinton, who has accused the brash billionaire of being "temperamentally unfit" to serve as commander in chief.
In addition to Morell, a group of former senior US government officials and military officers, including several who served in top posts under Republican presidents, denounced Trump in a recent letter and called Trump's recent comments wavering on the strength of the US's commitment to the NATO military alliance "reckless, dangerous, and extremely unwise."
While he spent much time attacking Clinton, the real estate mogul and GOP nominee also defended himself from accusations against his own character.
"All my life, I have been told, 'You have the greatest temperament,'" Trump said Friday in Des Moines. "I handle pressure."