KANSAS CITY, Mo. -- The urban district is beginning a search for its 25th superintendent in 39 years after its latest leader resigned amid mounting unhappiness among school board members.

Anthony Amato and the school board announced Wednesday night that Amato is stepping aside immediately but will stay on as a consultant through December.

Former Grandview Superintendent John Martin, who most recently was deputy superintendent for the St. Louis Public Schools, will fill in as the Kansas City district's 24th superintendent beginning Monday.

Soon after he started on July 1, 2006, Amato went to work making changes in programs and curriculum at a pace too fast for some. He had trouble hiring and keeping people in some top positions.

He received a critical performance review from the board last summer and was accused in a confidential complaint of using derogatory names for some board members when talking to staff.

Amato, whose tenure spanned 18 months and 22 days, has said those allegations were without merit.

He was not present at Wednesday night's meeting but issued a written statement.

"It has been a privilege to serve the students of this district, and I look forward to continuing to serve them in this period of transition," his statement said.

"It was a joint decision that we both made and that we both felt was in the best interest of the district," said board President David Smith.

Meanwhile, the board is preparing for a crucial accreditation review this spring as it continues a series of massive reforms that include universal pre-kindergarten, neighborhood schools for kindergarten through eighth grade, and specialty high schools.

"He did a lot to get us poised. ... But we agreed this would be a good time to get someone new to move the agenda," said Smith.

Smith said the board worked through many difficult issues in reaching its unanimous decision.

"Hopefully," he said, "the community will support a board working together like that."

But some remained skeptical.

"I'm sure the board wants to do what's best for the children of this district," said Dolores Arzola, chairwoman of the district's parent advisory committee, "but there has to be a better way to go about it than this."

State Sen. Yvonne Wilson, D-Kansas City, said recently that the board will need to be able to explain its reasons.

"If they (board members) don't have good evidence, I think you can just count on the state coming in," said Wilson, a former educator, has been one of the district's strongest allies in Jefferson City.

Although the state took control of the St. Louis district just six months after it ousted its superintendent of 15 months, that doesn't mean the same thing will happen in Kansas City, said Jim Morris, spokesman for the state's education department.

"The circumstances are not exactly the same," Morris said.

Problems in St. Louis also included conflicts in the school board and the district's financial distress. The state took over the district a year ago.

"That's in contrast with Kansas City, which has had a relatively calm period for its board," Morris said. "In the near term, the state board and our staff will wait and see how the district handles the transition."

Amato has been a polarizing figure in past jobs.

He won praise during 12 years he served as superintendent of what had been one of New York City's poorest-performing sub-districts.

The struggling Hartford, Conn., district saw immediate gains after hiring Amato in 1999, but his relationship with the board faltered and he left in 2002.

A year later, Amato took over New Orleans' school system, where he had strong fans and critics. He resigned in 2005.