Masch, reached on his cellphone on Friday, described his pending departure as a mutual decision. He said he would like to respond to questions about his tenure but had been put in a "difficult position" by district regulations.
"I am an employee of the School District right now, and as an employee of the School District there have been restrictions, the whole time I've been here, on my ability to talk to the media," he said.
Masch said he would be able to speak more freely after May 31.
People familiar with the district's inner workings said Masch had spent months looking for a new job but had been unable to find one that would match his current salary.
He is paid $180,000, a reduction that followed his demotion to "special adviser" in January, part of an administrative shuffle after Thomas Knudsen was named the district's chief recovery officer. Despite his adviser status, Masch has not participated in the administration's daily 8 a.m. budget briefings.
Masch had hoped to stay through the current fiscal year but was told his employment would end this month, sources said.
The district has cut millions of dollars in jobs, programs and expenses, but says it must slash $26 million more by June 30 - then face a shortfall of at least $217 million.
Knudsen says he wants to close 40 schools in 2013 and six in each of the next four years, to cut costs.
School Reform Commission Chairman Pedro Ramos has publicly criticized district fiscal policies under Masch and his predecessors, though never mentioning them by name. Instead Ramos has said more generally that the district has for years spent money it could not afford to spend and now is paying the price.
Shelly Yanoff, executive director of Public Citizens for Children and Youth, said, "Obviously, something went wrong with the estimates and the expenditures, but I think that when he was in Harrisburg and when he had been here before that, he always gave what I thought was an honest and plausible understanding of numbers, and how best to provide services with limited resources.
"The district needs to move on," Yanoff said. "But I don't think he should carry the blame for the mess that we're in by himself."
Masch joined the schools in July 2008 as chief business officer, with a salary of $220,000. Two years later, he lost some responsibilities, and his pay was reduced to $196,000 after a falling-out with then-Superintendent Arlene C. Ackerman. Knudsen demoted him further.
Democratic State Rep. Mike McGeehan, who represents Northeast Philadelphia, said legislators had long been frustrated by unreliable budget figures supplied by the district.
"In Harrisburg, we call it Maschematics," he said. "It's budgeting based on nothing, based on unknowns."
Masch and Ackerman believed "in the Hail Mary philosophy of budgeting - just like in football," he said. "You throw the ball in the air and hope somebody catches it."
The inability to depend on district budget figures has created mistrust in Harrisburg, he said. That fissure will take time and effort to repair, he said. Members of Philadelphia City Council have expressed similar sentiments.
McGeehan says the new members of the SRC and the administration are off to a good start, merely by relaying the hard truth of district finances.
One former district administrator, who declined to be named, said Masch relied on support from powerful Democratic politicians in Harrisburg to solve the schools' money troubles - Rendell was a fervent backer of public education, for instance. But those dynamics changed once Gov. Corbett and his Republican team took charge in the state capital.
Butkovitz, who clashed with Masch over district spending, said it was critical for the system to regain credibility if it hoped to "achieve financing or streams of financial support again - primarily from Harrisburg, but really from everyone who does business with them."
He reiterated his call for PICA, the Pennsylvania Intergovernmental Cooperation Authority, to take control of the district the same way it oversees the city government. When PICA was created in 1991, the city was in such desperate straits that it had no credibility to borrow or lend money.
"Now the School District has lost all financial credibility," Butkovitz said, adding that two things must follow, "one of which is that the people responsible have to leave. The other is that the structure has to be strengthened to assure third parties that it will never happen again."
Contact staff writer Jeff Gammage at 215-854-2415, firstname.lastname@example.org, or on Twitter @JeffGammage.
Inquirer staff writer Miriam Hill contributed to this article.