HARRISBURG - The top staff aide to Gov. Corbett is leaving the administration for a new job.

Corbett said Thursday he would nominate his chief of staff, William F. Ward, to fill a vacancy on Allegheny County Common Pleas Court. Ward will be replaced by Stephen Aichele, a lawyer from Chester County who currently works as Corbett's chief counsel.

The governor made his announcement in a prepared statement that gave no hint of the political turmoil that was said to have preceded the moves. He said a judgeship had been a lifelong goal for Ward, 60, a former state and federal prosecutor and longtime Corbett friend and confidant who, like the governor, hails from Allegheny County.

"For as long as I've known Bill, it's been his dream to be a judge," Corbett's statement said. "I'm happy to help make that dream happen, both for Bill and for the citizens who will benefit from his knowledge and integrity."

Ward's departure from his $154,000 post comes as Corbett has faced increasing pressure to address what some in top state Republican circles believe is the governor's growing image problem. The Inquirer reported Thursday that Corbett's top political advisers, supporters, and fund-raisers had been agitating for him to make changes to his senior staff.

Next week, a small group of Republican Party heavyweights, known as the governor's "kitchen cabinet," is to meet with Corbett in Harrisburg. Speaking on condition of anonymity, four people familiar with plans for the meeting said the "kitchen" group wants to air concerns - such as a feeling that the administration had not effectively sold Corbett's agenda to the public, and that the governor had paid a price in popularity.

Over time, the unofficial list of Corbett political advisers has included two Pennsylvanians on the Republican National Committee, Robert Asher and Christine Toretti; lawyer Jack Barbour, who heads the Pittsburgh law firm Buchanan Ingersoll & Rooney; Leslie Gromis-Baker, a strategist who worked on the campaigns of former Gov. Tom Ridge and President George W. Bush; and Nan McLaughlin, Corbett's Harrisburg-based fund-raiser.

Corbett spokesman Kevin Harley said Thursday that Ward's departure from the administration had nothing to do with outside pressure from politicos or anyone else.

"The governor is a very independent-minded man," Harley said.

Aichele, Ward's replacement, will step into what is arguably one of state government's toughest jobs after the governorship itself. A chief of staff is the governor's top ambassador and dealmaker, with powers that reach into all corners of policy and strategy.

Those who know him say Aichele has the political moves and savvy to do the job well. A real estate lawyer and onetime chairman of the Center City law firm Saul Ewing L.L.P., he has been involved in major deals over the years, including the Convention Center expansion.

Among Aichele's first orders of business will be to help repair Corbett's strained relationship with the Republican-controlled legislature.

As a former state attorney general who prosecuted top legislators for corruption and who was elected governor in 2010 on a pledge to change Harrisburg, Corbett came into office with a built-in adversarial relationship with some members of the General Assembly. Nonetheless, many in the legislature grumble that his office has done little over the last year and a half to change that dynamic.

Aichele is already part of a power couple in the administration: He is married to Carol Aichele, the former Chester County commissioner whom Corbett tapped last year to become secretary of the commonwealth, heading the department that oversees, among other things, state elections.

Aichele is to start his new job Tuesday. A new general counsel to Corbett has not yet been chosen.

Ward's confirmation to a judgeship in Allegheny County, where his family lives, is seen as likely - he received rave ratings from screening panels when he was considered for state and federal court vacancies over the last 18 years.

Pending his confirmation, he is to serve as a special adviser to Corbett, likely coordinating a team of staffers working on public employee pension reforms, Harley said.

Contact Angela Couloumbis at 717-787-5934, acouloumbis@phillynews.com, or follow on Twitter @AngelasInk.

Pittsburgh Post-Gazette staff writer Laura Olson contributed to this article.