Though the Trump campaign has not yet made an announcement, GOP campaign sources signaled to CNBC that Pence was Trump's vice president pick.
The New York businessman's campaign previously said he would make the official vice president announcement on Friday, but announced late Thursday that he is postponing the event after a truck plowed into a crowd celebrating Bastille Day in Nice, France.
@realDonaldTrump: In light of the horrible attack in Nice, France, I have postponed tomorrow's news conference concerning my Vice Presidential announcement.
In 2012, Pence was elected as Indiana's chief executive. In that role he has overseen tax cuts and signed state funding for pre-K education into law. He has presided over an economic recovery in the state during his time as governor that could give him a record to tout on the campaign trail.
Presumptive GOP nominee Trump, who is set to officially become his party's standard-bearer next week at the Republican National Convention in Cleveland, reportedly considered a number of prominent Republicans for the role.
Front-runners for the Trump VP slot also included former House Speaker Newt Gingrich, New Jersey Gov. Chris Christie, Sen. Jeff Sessions of Alabama, Oklahoma Gov. Mary Fallin and retired Army Lt. Gen. Michael Flynn.
Gingrich said that there would be "two pirates on the ticket" if Trump selected him. His appeal as a candidate, he said, was more "national," while Pence would offer "a certain value" because of how he plays in Midwestern swing states.