Mr. Rubio has acknowledged that his ascent to one of the most powerful positions in Florida government was marred by what he called “a series of terrible blunders.” He sometimes failed to treat his colleagues with courtesy. There was the time, for example, that many of his fellow Republicans learned of his campaign for speaker from reading about it in The Miami Herald, because he had not bothered to tell them first.

And he appeared willing, his detractors said, to abandon the interests of his district if the end result was a political promotion for himself. His election to speaker was made possible, in part, because of a bargain he had made: In exchange for votes from northern Florida lawmakers, former legislators and aides said, he agreed not to fight a measure that increased money for school spending in less populated, rural regions of the state and reduced it in denser, high-cost areas like Miami.

“He saw his path to be speaker, and it came at the expense of his constituents, literally,” said Christian Ulvert, a Democratic strategist who worked as a legislative aide at the time.

The image of Mr. Rubio as a young man in a hurry has persisted: He ran for United States Senate in 2010, taking on the sitting governor, Charlie Crist, and came from a double-digit deficit to defeat him. The presidential contest pits him against the former Florida governor who was once his supporter, Jeb Bush. And at a time when Republican presidential politics are being dominated by candidates who are outsiders to the political system, Mr. Rubio, with his ability to navigate intraparty politics and win over powerful benefactors, has proved himself to be a master of the inside game.

When Timing Is Everything

Two factors helped determine early on that Mr. Rubio would have a fruitful career in the State Legislature if he wanted one. The first was timing. Instead of being elected along with a whole class of freshman lawmakers, Mr. Rubio won a special election in January 2000 after a seat unexpectedly opened up near his neighborhood. (He did not even live in the district when he decided to run.)