Hillary Clinton named Virginia Senator Tim Kaine as her vice presidential running mate on Friday, adding a centrist former governor of a crucial battleground state to the Democratic ticket.
In a text message to supporters, the presumptive Democratic nominee said, "I'm thrilled to tell you this first: I've chosen Senator Tim Kaine as my running mate."
On Twitter a few seconds later, Clinton described Kaine as "a man who's devoted his life to fighting for others".
She called him "a relentless optimist who believes no problem is unsolvable if you put in the work to solve it".
Clinton's pick came a day after her opponent, Donald Trump, closed out the Republican Party's convention with a fiery address accusing her of "terrible, terrible crimes".
Kaine, 58, had long been a favourite for Clinton's ticket. Fluent in Spanish and active in the Senate on foreign relations and military affairs, he built a reputation for working across the aisle as Virginia's governor and as mayor of Richmond.
In a recent interview with CBS News, Clinton noted that Kaine has never lost an election during his lengthy political career and praised him as a "world-class mayor, governor and senator".
A favourite of Barack Obama since his early 2008 endorsement, the president told Clinton's campaign he believed Kaine would be a strong choice during the selection process, according to a Democratic familiar with the search who was not authorised to discuss it publicly.
Those views are not shared by some liberals in the Democratic Party, who dislike his support of free trade and Wall Street.
They pushed Clinton to pick Massachusetts Senator Elizabeth Warren or Ohio Senator Sherrod Brown, intensifying their criticism of Kaine late this week as his selection appeared imminent.
Clinton's campaign largely declined to comment on the search process, trying to keep the details - even the names of the finalists - under wraps to try to maximise the impact of their announcement.
She made no mention of her impending pick during a sombre meeting on Friday with community leaders and family members affected by the Pulse nightclub shooting in Orlando and a later campaign rally in Tampa.
She is expected to campaign with Kaine on Saturday morning at an event in Miami.
Before entering politics, Kaine was an attorney who specialised in civil rights and fair housing. He learned Spanish during a mission trip to Honduras while in law school, an experience he still references on the campaign trail.
During his political career, he's demonstrated an ability to woo voters across party lines, winning his 2006 gubernatorial race with support in both Democratic and traditionally Republican strongholds.
His wife, Anne Holton, is the daughter of a former Virginia governor, a former state judge and, currently, the state's Education Secretary. The couple has three children.
Clinton's plans to pick Kaine, hinted at for several days leading up her Friday announcement, had been viewed as a safe choice against the Republican ticket of Trump and Indiana Governor Mike Pence.
Some Democrats believe Trump's selection of Pence, a conservative white man from a largely Republican state, freed Clinton from pressure to add another woman or minority to her ticket.
Her short list included Warren, two Latino cabinet secretaries and New Jersey Governor Cory Booker, one of two black US senators.
Democrats argue that Kaine could help her to woo moderate and even some Republican voters turned off by Trump's provocative rhetoric, which was at the centre of his 75-minute acceptance speech on Thursday night.
Kaine got some practice challenging Trump's message when he campaigned with Clinton last week in northern Virginia, where he spoke briefly in Spanish and offered a strident assault on Trump's White House credentials.
"Do you want a 'you're fired' president or a 'you're hired' president?" Kaine asked in Annandale, Virginia, as Clinton nodded. "Do you want a trash-talking president or a bridge-building president?"