Name: Marco Antonio Rubio
What he does now: Rubio, 43, is the junior Senator from Florida. He currently serves on the Senate Intelligence, Foreign Relations, Small Business & Entrepreneurship, and Commerce and Science & Transportation committees.
What he used to do: Before his election to the Senate in 2010, Rubio was the Speaker of the Florida House of Representatives. His very first job was building cages for exotic birds.
Declared as a candidate: April 13, 2015 in Miami, Florida.
In his own words: "We've reached a moment now, not just in my career, but the history of our country, where I believe that it needs a Republican Party that is new and vibrant, that understands the future, has an agenda for that future and I feel uniquely qualified to offer that. And that's why I'm running for president."
Family tree: Rubio was born on May 28, 1971 to Mario and Oriales Rubio, Cuban immigrants who were naturalized when Rubio was a toddler. He met his wife, Jeannette Dousdebes, at age 19. After a long-distance courtship, he popped the question atop the Empire State Building, and she quit her job as a Miami Dolphins cheerleader. The couple now lives in West Miami with their four children, Anthony, Amanda, Dominic and Daniella.
What he believes in: Rubio, who has emphasized his Catholic faith on the campaign trail, was actually baptized as a Mormon at age 8, and attended the Church of Latter Day Saints throughout early adolescence. He then converted to Catholicism, making his first communion at 13, and now attends a Baptist church. When Time Magazine dubbed him the "Republican Savior" in 2013, he denounced the label: "There is only one savior, and it is not me. #Jesus," he tweeted.
Biggest childhood challenge: As a child, Rubio had to wear leg braces because his knees turned inward. Knowing his son hated the braces and was an avid football fan, his father, Mario, would impersonate Dolphins coach Don Shula over the phone, telling Marco he needed to wear the splints if he wanted to play for the Miami team. "I always wondered why Shula had a Cuban accent on the phone but not on TV," Rubio joked. He played football for a year at Tarkio College in Missouri before transferring to the University of Florida.
What he was like in school: In high school, Rubio was so disruptive that his teacher offered to give him a C- minus if he skipped class - and threatened an F if he returned to the classroom! "I finished my senior year with a 2.1 grade point average," Rubio admitted. He says he and his high school buddies used to sneak out to booze at the Biltmore Hotel in Coral Gables - the same hotel where he would later spend his wedding night and celebrate his Senate victory.
Debate Prep: To break the tension before debates, Rubio and his aides took to watching clips from the "This Is Spinal Tap," a mockumentary about a British heavy metal band. Just how worried was the senator-to-be about his underdog race against Charlie Crist? "I couldn’t bring myself to write a victory speech," he once said.
Might have wished for a do-over: Call it Rubio’s watershed moment. Tapped to give the official Republican response to President Obama’s State of the Union address in 2013, Rubio got a tad thirsty on-air. In the midst of his speech - and without breaking eye contact - he furtively reached for an off-screen water bottle and took a swig. Instead of panicking over the awkward moment, his PAC made hay out of the gaffe, releasing a branded water bottle - to the tune of more than $100,000.
Claim to fame: Rubio was reportedly on the short list to be Mitt Romney’s running mate in 2012. But according to the New York Times, there were "questions about how thoroughly he has been vetted." The spot ultimately went to Wisconsin Rep. Paul Ryan.
His record in the Senate: A bilingual Cuban-American son of immigrant parents, many Republicans hoped Rubio would appeal to Hispanics, but there’s long been an unspoken rift between Cuban Americans and other Hispanic Americans -- a divide that Rubio dismissed as "offensive." In 2012, he helped craft an alternative to the Democrats’ DREAM Act. The plan, which was later scrapped, would have allowed immigrants brought to the United States by their parents to reside in the U.S. legally. Rubio’s mother, who calls undocumented immigrants "pobrecitos" ("poor things"), urged compassion, asking her son not to "mess with them" too much.
One of his biggest disagreements with President Obama: Rubio, who grew up despising Cuban dictator Fidel Castro, is virulently opposed to Obama’s intention to restore diplomatic relations with Cuba. "Now dictatorships know that if they take an American, they may be able to get unilateral policy concessions," he told ABC. "Five years from now, Cuba will still be a dictatorship -- but a much more profitable one." The senator even objected when Beyonce and Jay-Z visited Cuba, supposedly for "propaganda purposes." (Maybe that’s just because he’s got a thing for the lyrical strains of Nicki Minaj.)
Guilty Pleasures: Besides "Spinal Tap," Rubio’s favorite movies include "Pulp Fiction" and "Wedding Crashers." He’s an avid football fan, and once said the coolest moment in his career was catching a pass from then-Gators quarterback Tim Tebow. He jams to R&B, hip-hop, "non-offensive" rap - but is definitely not a fan of disco.
ABC's Ali Dukakis contributed to this report.