Corbett, 60, is a former U.S. attorney for western Pennsylvania and was elected to a second four-year term as state attorney general last year.
He spoke to an enthusiastic crowd of several hundred people amid red, white and blue balloons. British rock group Genesis' "Turn It On Again" blared and a biographical video declared that it was time to "turn on the power of Pennsylvania."
The more than two-year-old corruption investigation by Corbett's office has led to the arrests of 12 people connected to the House Democratic caucus so far - including two former state representatives - but Corbett says more arrests are forthcoming.
In an interview after his announcement, Corbett dismissed criticisms that the investigation is politically motivated.
"We didn't go look for that investigation," he said, explaining his office learned of the allegations through newspaper articles. "We continue to investigate, and I know when the next round comes, I believe that complaint will go away."
He would not elaborate on where the investigation is headed, or when it may conclude.
"We're not going to hurry this along ... When those charges are filed, you're going to see, this has been done right," he said.
Corbett said his experiences as a ninth grade teacher, a father, an Army reservist, businessman and attorney have given him the experience for the job.
He also said something must be done about "the ridiculous amounts of money spent on WAMs", or "walking-around money," a term that refers to pork-barrel grants controlled by the Legislature.
While investing in communities is important, projects should be selected by informed decisions and true value, "not on the whim of a politician who is more concerned with given out an oversized check for a photo-op in order to win the next election."
Corbett said he would like to see Pennsylvania have a two-year budget process, which he said would allow agencies to better plan. And he said he would trim the state's automotive fleet of nearly 17,000, which he said costs some $72 million.
He touted his office's work to protect the elderly from scams and its child predator unit, which he said has taken 236 predators off the streets.
Pennsylvania must invest in education to improve the future work force, he said, but "We shall not confuse spending more money with improving education."
The state must also reduce the bureaucracy that makes it unfriendly to business, he said.
He also called for developing the state's natural resources, such as natural gas within the Marcellus Shale, while protecting the environment.
Corbett faces competition in the Republican primary from U.S. Rep. Jim Gerlach.
Gerlach, 54, a four-term congressman and former state legislator from suburban Philadelphia, announced his candidacy in July.
Gerlach, of Chester County, considers himself a moderate on social issues and touts himself as a fiscal conservative, saying he is devoted to cutting taxes and the bedrock Republican ideal of making government smaller.
Democrats considered potential gubernatorial candidates include Allegheny County Executive Dan Onorato, state Auditor General Jack Wagner and Philadelphia businessman Tom Knox.
Rendell, a Democrat in his second of two four-year terms, cannot run again for the office because of constitutional term limits.