Perry spokesman Mark Miner said the governor would make his intentions known on Saturday while visiting South Carolina and New Hampshire just as most of his presidential rivals compete in a test vote in Iowa.
Official word of Perry's entrance into the race came just hours before eight candidates, including GOP front-runner Mitt Romney, were to appear on stage during a nationally televised debate.
It wasn't much of a surprise. The longest-serving governor in Texas history has flirted with a presidential run since spring and has spent the past few months courting Republicans in early voting states and laying the groundwork for a campaign. He met privately with potential donors from California to New York and gave rabblerousing speeches to party faithful, casting himself as a fiscally responsible social conservative.
His intentions became even clearer over the past few days when officials disclosed that he would visit an important trio of states, a campaign-like schedule timed to overshadow the debate and the Iowa straw poll and, perhaps, wreak havoc on a field led by Romney.
Unlike others in the race, Perry has credibility with the at-times warring camps of the GOP's primary electorate. The pro-business tax-cutter who has presided over Texas' recent economic growth also is a devout social conservative with deep ties to some of the nation's evangelical leaders and Christians who dominate the pivotal Iowa caucuses.
But Perry also has never run a national campaign before, and it's unclear whether his Texas swagger and contemplation of state secession will sit well with GOP primary voters outside his state. Also an open question is whether he can raise the money necessary to mount a strong campaign against those who have been in the race for months or more.
He also may face fierce opposition from secular groups and progressives who argue that his religious rhetoric violates the separation of church and state and that his belief that some groups, such as the Boy Scouts of America, should be allowed to discriminate against gays is bigoted.
Within the Republican Party, Perry has enemies among moderates who question his understanding of national and international policy, including Sen. Kay Bailey Hutchison, who ran against him for governor in a bitter 2010 primary race.
An early adopter of tea party rhetoric, Perry even has some opponents in the movement. They complain he hasn't taken strong enough stances on state spending and illegal immigration, in part because as governor Perry signed a law making Texas the first state to offer in-state tuition to illegal immigrants and blasted a proposed border fence as "idiocy."
But before he starts pumping up supporters and wooing detractors, Perry will need to raise name recognition outside of Texas and conservative circles along with funds to fill a presidential campaign coffer. None of the money he's raised for Texas elections can be used in a national race, so he is starting from scratch.
The governor lags well behind previously announced candidates in both campaign workers and fundraising, mostly because he denied any interest in the presidency until late May. But the story he tells of having no interest in higher office until friends and family persuaded him to join the race adds to his carefully cultivated image as a Texas cowboy reluctantly riding into Washington to save the day.
The campaign will attempt to position Perry between the moderate Romney and Rep. Michele Bachmann of Minnesota, a tea party favorite.
Perry, who has been governor for 11 years, has touted his business-friendly job-creation skills in Texas as evidence of fiscal wisdom, giving him a chance to drain support from Romney, whose conservative record is burdened by the health care plan he implemented as governor of Massachusetts.
Social conservatives already support Perry in equal numbers to Bachmann, who never has held an executive office and who some Republicans consider too far right to beat President Barack Obama.
In polls conducted before he joined the race, Perry was in a statistical tie with Bachmann and within striking distance of Romney.
A career politician with 27 years in elected office, Perry calls his economic track record in Texas a model for the country, arguing that low taxes, little regulation and tough lawsuit restrictions help create jobs and attract business. Texas has fared better than most states during the Great Recession, though it has the highest rate of uninsured residents and among the poorest populations in the country.
Perry is a full-throated critic of both Democratic and Republican politics in Washington, advocating a weaker federal government with smaller entitlement programs and greater states' rights. He recently signed a pledge to cut spending, place a cap on future government expenses and balance the budget.
When asked during one of the first tea party rallies in Austin in April 2009 about a pre-Civil War clause that allowed Texas to secede from the Union, Perry said that if current federal government overreach continued, Texas could consider secession again.
The Texas governor's office, however, is the weakest in the nation. Voters elect top state executives and all judges, and the Legislature drafts the state budget and sets its own agenda. The veto is the only real power the Texas governor has other than appointing people to lesser government offices.
Democrats will highlight what they say are Perry's extreme right-wing beliefs, such as opposing the national income tax and the direct election of U.S. senators. States' rights is one of Perry's biggest issues, and he has said individual Legislatures should decide matters such as gay marriage and the legalization of marijuana. Those stances could draw conservative opposition - unlike his well-known love of guns.
Perry last year told an Associated Press reporter that he carries a laser-sighted pistol while jogging, and that he used it to shoot a coyote that threatened his daughter's dog that came along one day for a run. Texans touted what they called a heroic act, and gun manufacturer Sturm, Ruger & Co. Inc. issued a "Coyote Special" edition of its Ruger .380-caliber pistol complete with "A True Texan" emblazoned on the side.
How such stories play on a national stage could determine whether Perry can secure the GOP nomination. He'll also have to prove he has the skill to put on a national campaign.
While Perry looks good on television and gives fiery speeches, he is less disciplined in one-on-one encounters where he has made comments like the once about secession. He also did not fare well during the one debate he agreed to in his 2010 gubernatorial race, appearing awkward while repeating talking points rather than engaging the other candidates.