Trump says he'll hold a news conference on Saturday morning. He said he hoped Mr. Pence "will be effective in pulling the Republican ticket toward economic conservatism and limited government".
But Democrats were swift to eviscerate Pence and portray him as a divisive and intolerant ideologue out of touch with the diversifying nation. Presumptive Democratic nominee Hillary Clinton's campaign issued a video attacking Pence on issues related to women's health, gay rights and immigration.
Frustration among Trump and his advisers mounted because of news reports that Pence was the pick, sending top aides scrambling to insist no final decision had been made. Trump now claims that he opposed the Iraq war from the beginning even though he publicly said in 2002 that he supported an invasion.
Pence traveled from IN to New York Thursday afternoon, left to wait as rumors swirled that Trump might change his mind and select a vice presidential candidate with stronger foreign policy chops.
"I think he can do better with someone who has not capitulated on something as fundamental as religious freedom", Tony Perkins, president of the Family Research Council, told NBC News before the pick was announced. He's worked with the team in House leadership.
Pence is in NY meeting with senior advisers, the source said.
One of the first chores confronting Mr. Trump and his new running mate will be addressing their differences.
Trump tweeted the announcement on Friday morning. Trump's announcement came about an hour before that deadline.
Pence also last month criticized Trump's speculation that a federal judge born in IN was ruling against him in a lawsuit because of the judge's Mexican ancestry.
"Pence has a very latent and very robust sense of humor that will surface fairly quickly", Conway said.
Clinton's campaign signaled it was ready for such a brawl.
Pence is the most extreme pick in a generation and was one of the earliest advocates for the Tea Party.
"Mike Pence is that man", Ryan said in a statement.
Pence, a staunch conservative who served six terms in Congress, is seen as a running mate who would have the backing of GOP leaders and ease some of their concerns about Trump's political inexperience and volatile temperament. Picking Pence sends a message to these skeptics that maybe - just maybe - Trump will govern as a more traditional Republican than he sounds right now.
A favorite quote highlights how Pence might smooth some of the sharp corners of the Trump campaign and its supporters.
"Calls to ban Muslims from entering the US are offensive and unconstitutional", Pence wrote on Twitter at the time. Jeff Sessions (R-Ala.) and former House Speaker Newt Gingrich. Instead, Pence, under pressure from national conservatives, tepidly endorsed Trump's rival, Texas Sen. But some of Trump's children, who have been closely advising their father, were said to favor different candidates. The sweeping IN victory remains a point of pride for Trump that he often celebrates on the campaign trail. State law prohibits candidates from being on the ballot in two races.
Unlike Trump, however, Pence's taxes are unlikely to contain much of interest.