"He's proved what Democrats have been saying all along," Doyle said. "You can make things in America. You can pay people good wages and benefits - and you can succeed."
In making their endorsement, the leaders snubbed the only western candidate in the race, former Auditor General Jack Wagner, a late entrant with minimal funding who has also served as a state senator and Pittsburgh councilman.
The institutional support could add to the early momentum of the Wolf campaign, which has risen to the top in recent opinion polls, after a hefty series of TV ads financed in part by the $10 million in personal funds the former state revenue secretary has contributed to his own cause.
"I'm thrilled to be endorsed by all these people I really respect," Wolf said in an interview, adding that it would help his campaign "to the extent voters take their cues from leaders."
Some western Democratic leaders are backing other candidates in the May 20 primary, and an endorsement is no guarantee voters will follow.
Senate Minority Leader Jay Costa (D., Allegheny) said he favored U.S. Rep. Allyson Y. Schwartz of Montgomery County. Schwartz also has the endorsement of the Pittsburgh Federation of Teachers.
"She is best situated to beat Gov. Corbett and has the understanding of state government to be successful in office," Costa said in an interview. "Folks in Pennsylvania are ready for a woman governor."
Costa said Schwartz, a former colleague in the legislature, had the strongest base in the southeast, where primary turnout is likely to be higher than in the west because more congressional and legislative races are competitive there.
Nominating petitions are due Tuesday.
"These endorsements will have little impact on the outcome of the race," said Mike Mikus, campaign manager for Katie McGinty of Chester County, former head of the state Department of Environmental Protection. "Voters make up their own minds."
For good measure, McGinty has support from State Reps. Anthony M. DeLuca of Allegheny County and Peter J. Daley of Fayette County.
State Rep. Frank Dermody, the House Democratic leader, has voiced support for State Treasurer Rob McCord.
"No candidate in the primary has spent more time working for Western Pennsylvania," said McCord adviser Mark Nevins.
Other candidates running for the Democratic nomination to take on Gov. Corbett are John Hanger, a former DEP secretary and utility commissioner, and Lebanon County Commissioner Jo Ellen Litz.