"It's a big job with a lot riding on you. but you also know this is not a job that does not last forever".
Mr Ryan served more than 20 years in Congress, and while he appeared to share little in common with Mr Trump, he went on to play a central role in the current USA administration. GOP presidential nominee Mitt Romney won the district by 5 points in 2012, when Ryan was on the ballot as the vice presidential nominee. His tone was somber, and he read directly from prepared remarks. He said that the 2018 midterms and the chance that he wouldn't be speaker didn't factor at all into his decision to announce his retirement.
Rep. Charlie Dent, R-Penn., said it was too early to talk about who would replace Ryan. But Ryan downplayed that it would be a distraction.
This will kick off a battle for leadership between Majority Leader Kevin McCarthy, R-Calif., and House Majority Whip Rep. Steve Scalise, R-La., Ryan's top two subordinates.
Scalise demurred when asked if he would run for the speakership. He also added, "We [Republicans] will be fine as a majority". However, in March Ryan dismissed rumours that he wouldn't seek re-election.
The Ohio Republican, who retired from politics in 2015, once said he was "unalterably opposed" to legalising marijuana.
In January, Ryan said he would discuss re-election with his family before making an official decision.More news: Oil hits US$70 as China offers soothing words on trade
Ryan was a fiscal conservative, but his efforts to be a more pragmatic leader led to conflicts with hard-liners in the GOP conference.
The resignation of Mr Ryan - whose role as House speaker places him second-in-line to the president - will spark speculation about whether he could one day mount a White House campaign.
"Speaker Ryan is a good man who is always true to his word. We should all be grateful for his sacrifice and understand his desire to be a full time Dad".
"That was the end of that campaign, by the way, when they chose Ryan", Trump said. Pew Research Center statistics reveal that fathers and mothers are now equally likely to say parenting is extremely important to their identity.
Ryan's announcement, although rumored for months, still caught many Republicans by surprise on Wednesday. Ryan frequently notes that he does not have a residence in Washington, D.C. and that he sleeps in his office during the week.
"I wish Paul and his family much happiness and best of luck on all his future endeavors".
Democrats need just 23 seats in November's elections to regain control of the House for the first time since 2010.
"Despite our differences, I commend his steadfast commitment to our country", Pelosi said in a statement.
"Today I am announcing that this year will be my last one as a member of the House", Ryan said at a news conference.
On Wednesday, he that President Donald Trump, with whom he has had a sometimes hard relationship, with setting the stage to make that happen, adding "I'm proud of what we have accomplished". Steil did not immediately return an email seeking comment.