Updated at 7:34 p.m. ET: Donald Trump has postponed the announcement of his running mate due to the deadly truck attack in Nice, France. A news conference had been scheduled for Friday.
Donald Trump is expected to officially tap Indiana Gov. Mike Pence as his running mate Friday, announcing his veep pick with a press conference in New York City.
The 57-year-old Pence, who first endorsed Texas Sen. Ted Cruz in the Republican primary race, isn't particularly well-known among American voters, according to a recent CBS News poll, but Trump's choice is sure to propel Pence into the national spotlight.
As Pence joins Trump on the GOP's general election ticket, here are five things to keep in mind about the Indiana Republican:
1. He's a career politician
Pence, who graduated from Hanover College and earned his law degree from Indiana University, first waded into national politics in 1988, challenging Democratic Rep. Philip Sharp in Indiana's second district when he was 29 years old. He lost that bid -- and his next -- to Sharp, before winning a seat in 2000. He then served for six terms in the House, where he chaired the conservative Republican Study Committee and was also part of the Tea Party caucus.
In 2012, Pence won election as governor of Indiana, after incumbent Republican Gov. Mitch Daniels was term-limited out.
2. He's a culture warrior
On Capitol Hill, Pence once famously described himself as "a Christian, a conservative and a Republican -- in that order."
That statement has proved true throughout his political career, with Pence positioning himself as a culture warrior both in Congress and in the governor's mansion.
As a U.S. representative, Pence was known for single-mindedly tackling social issues like abortion. In 2011, Pence spearheaded the effort to defund Planned Parenthood over its abortion services, even telling MSNBC that "of course" he was willing to risk a government shutdown over the fight.
In March of 2016, Pence, as governor, also signed a bill preventing women from obtaining an abortion because of a fetus' genetic abnormalities. The Indiana legislation would also have held doctors legally liable if they knowingly performed an abortion for those reasons. A federal judge blocked the law from taking effect last month.
In 2015, Pence was propelled onto the national stage when he signed into law the widely criticized Indiana's Religious Freedom Restoration Act, a law that several businesses panned as allowing for the discrimination of gays and lesbians.
At the time, Pence defended the measure to ABC News, maintaining that "this is not about discrimination -- this is about empowering people to confront government overreach."
But after a brutal backlash where several corporations threatened to boycott the state of Indiana, Pence signed a revised version of the the law that included language prohibiting discrimination.
3. He's been a syndicated talk radio host
After leaving his job as president of the Indiana Policy Review Foundation, Pence launched his career in talk radio. First, he hosted "The Mike Pence Show," which aired on 18 stations throughout the state for a few hours each morning. Before his stint in Congress, he hosted a weekend political talk show in Indianapolis.
His broadcast experience could be valuable as a vice presidential nominee, especially when it comes time to face his Democratic opponent when they debate each other this fall.
4. He splits with Trump on some key points
Pence has not seen eye to eye with Trump on some key policy areas. On the same day that Trump announced his proposed plan to ban Muslims from entering the U.S. last December, Pence expressed opposition.
Calls to ban Muslims from entering the U.S. are offensive and unconstitutional.— Governor Mike Pence (@GovPenceIN) December 8, 2015
At the same time, Pence opposed allowing Syrian refugees to settle in Indiana and directed state agencies last November to suspend their resettlement policy there. A federal judge later ruled that Pence's order "clearly discriminates" against refugees from a particular country.
Pence has also publicly supported President Obama's landmark trade deal, the Trans Pacific Partnership (TPP) -- a policy that Trump has repeatedly referred to on the campaign trail as a "rape" of the U.S. economy.
Pence tweeted his support for TPP back in 2014:
In contrast, Trump has threatened to rip up America's existing trade deals, despite vehement criticism from Republican-leaning business groups.
While Trump now claims that he opposed the Iraq war from the beginning -- even though he publicly said in 2002 that he supported an invasion -- Pence voted in Congress for the authorization to use military force in Iraq in October 2002.
And long before he became an elected official, Pence wrote a 1991 essay titled, "Confessions of a Negative Campaigner" in the Indiana Policy Review in which he claimed that "negative campaigning is wrong." He continued, "It is wrong, quite simply, because he or she could have brought critical issues before the citizenry."
Pence does agree with Trump on taxation -- as governor, he's fought for and successfully signed into law a corporate income tax rate of 4.9 percent, which will make Indiana the state with the second lowest corporate tax rate in the country.
5. He once wrote an op-ed that smoking doesn't kill
In the early 2000s, Pence wrote a few op-eds including one in which he claimed that "smoking doesn't kill," according to Buzzfeed.
"Time for a quick reality check. Despite the hysteria from the political class and the media, smoking doesn't kill," he wrote. "In fact, 2 out of every three smokers does not die from a smoking related illness and 9 out of ten smokers do not contract lung cancer. This is not to say that smoking is good for you...news flash: smoking is not good for you...The relevant question is, what is more harmful to the nation, second hand smoke or back handed big government disguised in do-gooder healthcare rhetoric."
According to the Centers for Disease Control and Prevention (CDC), cigarette smoking causes more than 480,000 deaths each year in the U.S. The CDC says that means it's nearly one in five deaths. It also says that smoking causes about 90 percent of all lung cancer deaths in men and women.