SAN DIEGO -- The San Diego Unified School District's chief special projects officer was appointed interim superintendent to replace Terry Grier, who resigned 18 months into a four-year contract, it was announced Friday.

Bill Kowba also served as interim superintendent when Carl Cohn, the superintendent before Grier, resigned.

"Mr. Kowba is an experienced leader with the skills needed to lead our organization at this difficult time," Shelia Jackson, president of the SDUSD Board of Education, said in a letter to SDUSD employees.

Kowba has also been the district's chief financial officer and chief logistics officer.

Grier's resignation came Thursday, immediately after he was formally offered and accepted a job with the Houston Independent School District.

As provided for in his contract, Grier, 59, gave San Diego Unified a 30-day notice. He will work through Sept. 18 and use 22 vacation days.

The Houston district, which serves about 202,000 students and is nearly twice the size of San Diego Unified, will pay Grier a $300,000 salary to be its superintendent, with an annual bonus that could increase from $50,000 to $80,000 over time, The San Diego Union-Tribune reported. He also will receive contributions to a retirement account.

San Diego Unified, which has around 135,000 students, paid Grier a salary of $269,000 and offered him up to $10,500 in annual bonuses.

Grier's departure came as no surprise to district officials because the Houston district named Grier its sole finalist three weeks ago. Under Texas law, the school board was forced to wait 21 days before offering its top candidate a contract.

San Diego Unified hired Grier to be its superintendent amid a financial crisis, with the recession taking hold and California's budget woes carving a huge chunk out of funding to local school districts.

While in San Diego, Grier has grappled with severe budget cuts and a labor-friendly school board majority.

Jackson said the SDUSD board will meet over the next few weeks on how to identify a permanent superintendent to replace Grier.

"We do not plan to rush to fill the superintendent position," she said. "We believe we should consider our needs carefully and will seek staff and community input on what our priorities should be for the next superintendent of the district."