Hillary Clinton chooses Sen. Tim Kaine as her running mate

Hillary Clinton chose Sen. Tim Kaine as her running mate Friday night.

Kaine, 58, a former governor of Virginia, brings a number of credentials to the ticket and has been widely viewed as a safe pick. In the Senate, he serves on the Armed Services and Foreign Relations committees, giving him national security and foreign policy experience. He also speaks fluent Spanish, and would help Clinton in his home swing-state of Virginia.

Clinton called Kaine at 7:32 ET on Friday with her offer, and then called President Barack Obama 16 minutes later with her decision.

Two of the top contenders mentioned in recent days were Kaine and Agriculture Secretary Tom Vilsack. However, a number of other potential running mates have been bandied about in the press, including Labor Secretary Tom Perez, Secretary of Housing and Urban Development Julian Castro, and retired admiral James Stavridis.

A poll of CNBC readers from earlier this summer on who Clinton should pick to join her on the ticket had Massachusetts Sen. Elizabeth Warren in first place, with Kaine in second and Vermont Sen. Bernie Sanders in third.

The Democratic presumptive nominee's decision comes on the heels of the Republican National Convention, which drew to a close Thursday in Cleveland.

NBC News reported that Clinton's first joint appearance with her running mate will take place Saturday at a rally in Miami. The announcement puts one of the final pieces in place as Democrats prepare to gather in Philadelphia next week for the party's convention.

Clinton's opponent Donald Trump weighed in Saturday morning, with the obvious intent to woo Bernie Sanders supporters.

Republicans, too, had a response.

"Hillary Clinton's choice of Tim Kaine does nothing to unify a fractured Democrat base which is repelled by her dishonesty and cronyism," said RNC Chairman Reince Priebus. "After spending last week pandering to grassroots Democrats with Bernie Sanders, Hillary Clinton has chosen someone who holds positions that she's spent the entire primary trying to get to the left of.

"Ultimately this is a ticket that represents one thing: four more years like the last eight, just with more corruption and scandal," he added. "A Clinton-Kaine administration will push our country further down the path President Obama has led us on and that has made us less safe, less prosperous, and less free."

While Clinton and Kaine did not overlap during their time in the Senate, they have campaigned together on the trail this cycle, making two joint stops according to NBC News. In an interview with Charlie Rose, Clinton lauded Kaine as a "world-class mayor, governor and senator." Kaine led the city of Richmond as mayor before running for statewide office.

When it comes to his economic record, Kaine can claim to have steered Virginia through the worst of the financial crisis during his time as governor. While Virginia's jobless rate leaped more than 4 percent during his four-year term, he left the Commonwealth with a rate still below the national average.

The state's strong services sector has also helped maintain relatively solid wage growth, with Virginia ranking roughly in the middle in terms of median annual salaries. However, residents of the state can rightly complain about their taxes, as Virginia residents are the 12th highest taxed of the 50 states, according to the Tax Foundation.

—CNBC's John Schoen contributed to this report.

UPDATED: This story was updated to include responses from Donald Trump.