Cuyahoga County Executive Ed FitzGerald (D) officially kicked off his campaign against Ohio Gov. John Kasich (R) on Wednesday, launching a bid to take on a onetime very unpopular governor whose image has improved dramatically in the last two years.

FitzGerald is the early front-runner for the Democratic nomination. His decision to run has been widely expected in recent weeks; he launched an exploratory committee in early March and has caught the attention of national Democrats.

The Democrat has an intriguing background. He is a former mayor and FBI special agent. And at just 44, he's pretty youthful in political years.

"As an FBI agent and county executive, Ed FitzGerald's career has been defined by rooting out corruption, restoring integrity in government, and promoting policies focused on job creation rather than corporate giveaways," said Democratic Governors Association Chairman Peter Shumlin of Vermont.

Not too long ago, Kasich looked like he was going to have a near impossible time winning reelection, with an approval rating as low as 30 percent in 2011. Since then, he's been on the mend, against the backdrop of an economy in Ohio that has also been recovering. More than half of Ohio voters said they approve of the job he is doing, according to a recent Quinnipiac University survey.

But the same poll showed that Kasich starts with less than 50 percent support against FitzGerald, suggesting a tough campaign is in the offing for him. Republicans began taking aim at the likely Democratic nominee on Wednesday, noting other higher profile Democrats opted not to run, and linking him to a corruption probe in which he was not charged.

“After failing to recruit a more experienced candidate, Democrats are now stuck with Ed FitzGerald’s brand of pay-to-play and corruption politics," said Republican Governors Association Executive Director Phil Cox.