MIAMI — Bill Clinton is lending his political star power to Democrat Charlie Crist, a former Republican governor who is locked in a tight race for his old job in the nation’s largest swing state.

The former president on Friday headlined a rally in Miami where he implored Democrats to defy historical trends and turn out to vote in November.

“We’re great at doing what’s right if there’s a presidential election on the ballot but we’re not nearly as good as our Republican opponents are at showing up in the midterm elections,” Clinton said. “The whole shebang is going to depend on who shows up.”

Speaking to several hundred supporters, Clinton painted Crist as a bipartisan conciliator who would rebuild the middle class by raising the minimum wage, ensuring equal pay for women and expanding Medicaid to hundreds of thousands of Floridians. He cast incumbent Republican Gov. Rick Scott as a multimillionaire who has favored corporate interests.

“If you’re trying to raise a kid or two on the minimum wage, you need somebody with the facts to be on your side, and Charlie Crist will be on your side,” Clinton said.

The Clinton rally was the first in a series of high-profile events featuring Democratic heavyweights designed to boost party enthusiasm for Crist, a former Republican governor who has run four statewide races on the Republican ticket as well as one as an independent.

Massachusetts Gov. Deval Patrick is set to appear with Crist in Florida on Monday, while Maryland Gov. Martin O’Malley, who is weighing a 2016 White House bid, will campaign with him Sept. 20.

While Crist easily secured his new party’s nomination last month, his campaign must still reassure some of the key Democratic activists who have opposed him throughout his political career. He also must work to overcome an unprecedented barrage of negative ads.