"I also fully support and endorse Sen".
Trump's announcement, made during a campaign stop in Green Bay, came just a few days after he gave a shoutout to Ryan's primary challenger and proclaimed he "was just not there" when it came to endorsing Ryan.
Trump had balked at endorsing Ryan on Tuesday in an interview with The Washington Post, a move that intensified concerns about his presidential campaign within the GOP as Trump already faced controversy over his criticism over the weekend of the parents of an American soldier killed in combat.
Trump's previous nonendorsement of Ryan and US senators John McCain, R-Ariz., and Kelly Ayotte, R-N.H., was just part of a growing onslaught of controversy and tanking poll numbers for the GOP nominee since the Republican National Convention just two weeks ago.
Presidential nominee Donald Trump ended the endorsement drama Friday night while in Green Bay at a rally.
"He's a good man and good guy", he added. "She will be so bad for our country and we can't let it happen", Trump said.
In an interview with USA Today published on Monday, Trump was asked about the sexual harassment accusations against Fox News boss Roger Ailes, who resigned last month amid the scandal.
On Tuesday, Trump told the Post that Ayotte had given him "no support - zero support", later adding "We need loyal people in this country".
The tale of two states underscores Trump's mounting challenges during one of the most tumultuous weeks of his unorthodox campaign.
Meanwhile, rival Hillary Clinton appeared increasingly bullish Friday about Democrats' retaking the Senate and picking up seats in the House of Representatives.
"It doesn't make me feel good when people say those things, and I recognize that I have work to do", Clinton said.
Eager to change their minds, Trump unleashed a torrent of insults at Clinton throughout the day.
Trump acknowledged during his campaign event Friday that he would need the help of various party factions.
"We will have disagreements", Trump said just days after refusing to endorse the Wisconsin Republican. Big, big tent, remember?
"My 80% friend is not my 20% enemy", Trump said, quoting President Ronald Reagan.
Capping the lousy week, Mr Trump admitted Friday that he wrongly claimed to have seen secret Iranian footage of US$400 million in hard currency being delivered to Tehran as payment for the release of U.S. prisoners.
Priebus said in a tweet on Friday that he and his wife voted for Ryan. He repeated several times throughout the morning that he was not seeking Trump's endorsement and that his constituents - "our employers in Wisconsin" - are his top priority. "I take it seriously", she said.
Ryan has yet to respond to Trump's endorsement. "But I still think it's hard if you are dividing, to be able to win in Ohio".
"I love babies. I love my children".
The Republican nominee tried to stay on message, hammering his opponent Hillary Clinton.
At a rally in Des Moines, Mr Trump mostly stuck to his central charge that Mrs Clinton was the "queen of corruption", and defended himself against her charge that he was temperamentally unfit for the White House. He was Mitt Romney's running mate in 2012. Tim Kaine (Virginia), also was in Wisconsin on Friday.
Donald Trump is drawing tens of thousands to his rallies. "You're going to keep your place in history". "You've done it again and again and again".