Texas Sen. Ted Cruz won Iowa with 28 percent of the vote, followed by Trump's 24 percent and Rubio's 23 percent. Rubio's result was better than anticipated, as polls predicted he would trail Trump by 11 percent. He fell short of Trump by about 300 votes.
"For months, they said we had no chance ... They told me I had no chance because my hair wasn't gray enough and my boots were too high," Rubio said during a speech. "They told me I needed to wait my turn, that I needed to wait in line. But tonight here in Iowa the people of this great state have sent a very clear message."
Rubio's campaign strategy in Iowa was to focus mostly in the state's metropolitan areas, which are more moderate. It appeared to have worked. Rubio won five of Iowa's most populous counties, including Polk County, where Des Moines, the state capital, is located. But he didn't win in any of the other 89 counties in the state.
Any momentum Rubio can gain from a near-second finish in Iowa could help the Florida Senator in New Hampshire, where the first-in-the-nation primary will be held on Feb. 9. The Rubio camp is aiming for a second-place finish in New Hampshire with a first-place victory in South Carolina's primary on Feb. 20.
Rick Tyler, a spokesman for Cruz, downplayed Rubio's view that he was victorious in Iowa.
"Marco Rubio is going to come in third," Tyler said. "Coming in first is better than coming in third."
Rubio is now seen as the Republican establishment's candidate of choice, facing off against anti-establishment candidates Cruz and Trump.
"We are going to unify this party, and we are going to unify the conservative movement," Rubio said Monday.