The hiring of controversial consultant Mary Guinn as interim deputy superintendent of the Buffalo Public Schools is likely to breed even more dissension and hard feelings on a school board that has been bitterly divided over Superintendent Pamela Brown’s leadership.

Guinn has been seen by many on the board, in the community and within the central administration as a polarizing figure. Guinn helped spearhead Brown’s reorganization of the central office, and was heavily criticized both for her high consultant pay and for her assuming authority as a consultant that many other top-level administrators considered unwarranted.

Brown and her board supporters, meanwhile, have previously argued that the superintendent cannot effectively focus on district planning and big-picture concerns to turnaround struggling schools without a second-in-command to handle the day-to-day operations in a 34,000-student district.

The board’s vote to rehire Guinn for 90 days came at the very end of the meeting, around 9 p.m., after all media except The Buffalo News had left, as well as all but a handful of people in the audience.

Brown said Guinn will begin work next week while the superintendent continues her search for a permanent deputy superintendent. She said Thursday that Guinn is not being considered for the permanent position.

The superintendent dropped the bombshell hiring request on board members Wednesday night during a closed session that was called after all regular business was completed. The board met behind closed doors for more than an hour before coming out to vote on Guinn around 9 p.m.

Though Wednesday’s 5-3 vote for her hiring would have been split no matter when Brown made her recommendation to hire Guinn, the fact that Brown apparently hid her intentions from several board members until late last night launched a firestorm of criticism, which is likely to continue in the coming days.

Guinn was hired last March with private grant money through Say Yes, the Oishei Foundation and Community Foundation of Greater Buffalo. Guinn was to serve as interim deputy superintendent for three months while the district hunted for a permanent deputy.

But no deputy was ever hired. Instead, Brown asked Guinn to stay on as a consultant and agreed to pay Cross and Joftus $432,000 for a one-year period ending in June 2014. The prior School Board approved this arrangement.

Guinn previously served as an educational consultant with Evans Newton, then Cross and Joftus, since July 2012. She has also served in various roles as principal and deputy superintendent for various districts.

“In spite of any questions that exist,” Guinn told the board in September, “I have worked very hard throughout my career, and I have documented facts of the progress that has been made throughout the district.”

She was superintendent in Gary, Ind., for more than five years, until 2004, when the board voted not to renew her contract, citing declining test scores as a factor in the decision.

She then worked in Tulsa, Okla., for five years as deputy superintendent for strategic planning. During that time, she said, the number of “priority schools” in bad standing with the state fell from 36 to six.

She lost her post there in a restructuring.

In September 2011, she was named head of Esperanza Charter School in New Orleans. She resigned after less than a year.

Guinn has previously been named a finalist for the superintendent’s post in Monroe, La., and also was a finalist for the superintendent’s post in Kansas City, Mo., in 2009.

The Cross and Joftus contract, under which Guinn was initially hired here in Buffalo, covered the compensation of Guinn, Scott Joftus and a company analyst. Of the overall amount, $290,359 is paid to Guinn, excluding thousands of dollars in additional travel and lodging expenses.

Guinn, who lives in Little Rock, Ark., charged the district nearly $10,000 in travel expenses for July and August, according to Cross and Joftus. That includes $3,708 for her stay at the Embassy Suites hotel.

In September, board members Sampson, Paladino, John Licata, Theresa Harris-Tigg and Jason McCarthy wanted to know why Guinn was signing district documents and time cards, why she is being copied on administrative emails to principals, and why she has presided over the superintendent’s executive cabinet meetings and a School Board committee meeting.

Since then, Sampson, Paladino, Licata and McCarthy have been adamant in their opposition to Guinn’s hiring. McCarthy was not present at Wednesday’s board meeting.