Shapiro will formally launch his campaign Wednesday morning in Pittsburgh and then hold a “hometown rally” in Montgomery County later in the day, his campaign said.
Pennsylvania Gov. Tom Wolf, a Democrat first elected in 2014, is term limited, leaving the field wide open.
A handful of Republican candidates, including former US Rep. Lou Barletta, former US attorney Bill McSwain and GOP strategist Charlie Gerow, are also vying to be the next governor.
In his campaign video, Shapiro took a swing at his Republican rivals, accusing them of wanting “to lead us down a dark path, undermine free and fair elections, strip away voting rights and permanently divide us.”
Shapiro was narrowly elected the state’s top prosecutor in 2016. He formerly served on the Board of Commissioners in Montgomery County and in the Pennsylvania state House.
Shapiro was reelected in 2020 by nearly 5 percentage points and started his second term as attorney general in January.
He joins Arizona Secretary of State Katie Hobbs in running for governor after defending the 2020 vote count in their states. Hobbs launched her campaign for Arizona governor in June.
This story was updated with additional information.