With Virginia Sen. Tim Kaine at her side, Hillary Clinton appeared at Florida International University on Saturday in Miami and delivered a speech to thousands of supporters.

Her speech started off with her bashing her Republican opponent Donald Trump. She said that at next week's Democratic National Convention in Philadelphia, she and Democratic leaders will talk about building bridges, not building walls, a shot at Trump’s proposal to build a wall around the Mexican border.

But she praised her new running mate.

"Tim is everything Donald Trump and Mike Pence are not … he is a progressive who likes to get things done. That’s just my kind of guy," Clinton said about Kaine.

She talked about Kaine's law career and how he became a civil rights lawyer, well also highlighting his "courage" to take on the NRA and how he fought to make sure a mentally-ill person cannot own guns. 

But she turned it back to the convention in Philadelphia next week.

People will see a "very different kind of vision" at the DNC on Monday, Clinton said, as the crowds chanted "USA! USA!" She told the crowd that her campaign will be hiring campaign workers in Florida.

After she introduced Kaine, he spoke in Spanish to the supporters as they cheered. 

"I'm grateful to this country which has given me so much," Kaine said, as he mentioned his wife Anne and his three children. "I'm the luckiest dad and the luckiest husband in the world."

His son Matt is a Marine and was looking on at his father with his fiancé. Matt Kaine will be deployed to Europe to "uphold America's commitment to our NATO allies," his father said, mentioning how military members need an experienced person in the White House like Clinton. 

But the elder Kaine also attacked Trump, saying how the Republican candidate said that John McCain was not a war hero because he was captured. 

"He leaves a trail of broken promises and wrecked lives everywhere he goes," Kaine said about Trump, adding, "Hillary Clinton is the direct opposite of Donald Trump."

He talked about his experiences in Honduras, how he met his wife Anne and how he started his career in politics. He highlighted how he invested in cleaning the Chesapeake Bay and his work in advancing education. He even mentioned how his wife's father, A. Linwood Holton Jr., was a governor of Virginia in the 1970s.

Clinton fought for health care for children and people with disabilities, Kaine mentioned. 

"She always has delivered for them," Kaine said, as she highlighted her career. "She has always delivered."

"Here is how Hillary and I will continue that work with a strong, progressive agenda. We are going to make the American economy work for everybody, not just those at the top," he told the crowd. "We will make college debt free for everybody."

Kaine also mentioned how Trump has not shown his tax returns, in addition to saying how Clinton and Kaine have a plan to help illegal immigrants to become legal citizens.

Kaine recounted the Virginia Tech shooting, which left 32 dead. He said that he wants to close the gun show loopholes and keep guns out of the hands of terrorists and the mentally ill, adding that gun owners and NRA members have agreed with his proposals. 

But Trump became the topic again, as Kaine asked the crowd if they want a "fired president" or a "hired president".

"America was not built on fear," Kaine paraphrased former President Harry S Truman. "Tough times don't last, but tough people do."

He closed his speech by telling the crowd to help make Clinton the next president of the United States of America.

 

Tim Kaine's career in politics

Kaine has held three big-time political positions. He is a former Governor of Virginia, former Chair of the Democratic National Convention and now a U.S. Senator in Virginia. He is one of only 20 people to hold all three of those offices.

Plus, he was a mayor of Richmond. 

Virginia is one state where Clinton hopes to lock up this fall.

Kaine was widely rumored to be Clinton’s vice presidential running mate. He is considered to be a safe choice for Clinton.

He supported Barack Obama in 2008, but this time around he has been an early supporter of Clinton. At an event last week, he spoke about Clinton.

"We were ready for Hillary because Hillary's ready for us. Hillary is ready for Virginia. Hillary is ready to be President. Hillary is ready to be our leader. Hillary is ready to make history," said Kaine.

The 58-year-old Kaine speaks fluent Spanish. Hillary hopes that will help solidify her support with Hispanic voters.

As governor of Virginia, he dealt with a Republican-controlled general assembly that blocked some of his primary goals, including early education and repairing the state’s transportation system.

He also dealt with an economic crisis and the mass shooting at Virginia Tech.

His leadership resulted in statewide mental health reforms after the shooting.

However, a few things in his background may bring concerns as he and Clinton go down the campaign trail.

Kaine supports making higher education more affordable, although he has mixed feelings about free tuition at public colleges for everyone.

He supports cutting taxes for most Americans except for the very wealthy.

Kaine recently signed two letters urging federal regulators to go easy on big banks, community banks and credit unions.

Some liberal groups were upset about those letters, which asked banking regulators to loosen the amount of capital large banks hold.

The second letter asked the protect community banks and credit unions from consequences that would negatively impact their businesses.

As governor, Kaine said in 2008: "We're not going to drill our way out of the long-term energy crisis facing this nation." But in 2013, he and Sen. Mark Warner, D-Va., sponsored legislation that would have set a five-year leasing plan allowing oil drilling off Virginia's coast and providing at least 35 percent of revenues to the state. In 2015, Kaine again joined Warner and a group of East Coast senators pushing an offshore drilling plan.

Oil and gas companies have donated nearly $60,000 to Kaine for his 2011 campaign, including $35,000 from Dominion Resources Inc., the Richmond-based utility that supplies electricity and natural gas to Virginia and other neighboring and eastern states.

Dominion donated more than $250,000 to Kaine's statewide political campaigns and inaugurations between 2001 and 2008, according to the Virginia Public Access Project, a nonpartisan open government group.

Environmentalists said Kaine, as governor, helped undermine clean-coal and other anti-pollution efforts in Virginia. Vivian Elizabeth Thomson, a University of Virginia professor who served on the state's Air Pollution Control Board under Kaine, said his administration undercut their efforts to impose tough standards on a coal-fired Dominion power plant in Wise, Virginia.

And he has said that he personally opposes abortion, according to the Associated Press.

Clinton will formally introduce Kaine as her running mate at a campaign stop in Miami Saturday, where News 13 will have live coverage.

The Associated Press and CNN contributed to this report.