Forrest Claypool’s cover-up of his top attorney’s ethics violation has cost him his $250,000-a-year job leading the country’s third largest school system.

But the cover-up also cost city taxpayers $120,000 to date, according to a review of legal bills and the damning 103-page internal report that led to Claypool’s recent ouster from the Chicago Public Schools.

The money was spent on four outside law firms even as CPS slashed school spending.

Claypool consulted two law firms, paying a total of $9,204, on whether then-CPS General Counsel Ronald Marmer could supervise his former law firm’s legal work at CPS while he still collected annual severance from the firm of $200,000.

A third firm, paid $71,344.50, gave advice on Marmer and initially represented the Board of Education during Inspector General Nicholas Schuler’s probe, leading the IG to call for the firm to be replaced. Board members heeded that advice and replaced the third firm with a fourth one. That most recent law firm got $40,219.46, and still represents the Board of Education.

Prompted by Chicago Sun-Times’ reporting in July 2016, Schuler found that Claypool shopped around for an attorney until he found one who said Marmer could legally continue to oversee the firm’s work on a lawsuit against the state, as he had been doing.

That opinion came from J. Timothy Eaton, an attorney at Taft, Stettinius & Hollister LLP, whom Claypool had known since college. Unlike the six previous attorneys and the inspector general, Eaton determined that Marmer wasn’t violating the code. Eaton wrote that Marmer didn’t have  an “economic interest” in the firm, but initially ignored the question of whether Marmer had a “business relationship” with it, which is defined in CPS’ ethics code as earning more than $2,500 a year, which also would have broken the rules.

Eaton charged $1,475 for that opinion, according to bills CPS provided only after the Sun-Times sued under the Freedom of Information Act. Eaton later wrote a second opinion after realizing other attorneys had addressed the “business relationship” part of the ethics code.

It turns out that a second partner from that firm also worked on those opinions, bringing the total spent on them to $3,422, according to additional bills CPS previously withheld.

Eaton said this week in an interview that he didn’t initially address the “business relationship” part of the code because he “didn’t see much merit” in it.

Eaton has previously given $5,000 in contributions to Claypool’s runs for public office, but Eaton insisted his legal opinion had nothing to do with his previous support for Claypool.

The rest of the $71,344.50 in bills from Eaton’s firm stemmed from its representation of school board members once Schuler began investigating. Schuler wrote privately to the school board in June to urge them to waive the attorney-client privilege blocking him from witnesses and documents, blaming “the heavy hand of J. Timothy Eaton” for blocking his access.

Eaton denied that characterization: “The board decided to invoke the attorney-client privilege, and I was simply protecting their privilege.”

Eaton’s firm was replaced in July by McDermott, Will & Emery, which agreed to represent board members for $500 an hour, about $200 more than CPS’ usual attorney rate, up to $250,000. They’ve billed $40,219.46 through November.

Two McDermott attorneys joined the school board in a closed meeting the day after Schuler presented his report. The same lawyers also accompanied Claypool into his final news conference at CPS to announce his resignation.

CPS spokesman Michael Passman declined to comment on the legal spending.

Claypool, the third schools chief Mayor Rahm Emanuel has appointed since 2011 and the second ousted by scandal, ends his tenure at CPS on December 31. Marmer has also resigned.

In the spring of 2016, the CEO ignored the advice of four CPS lawyers and two outside ones before touting what Schuler called the “incorrect and materially deficient” opinion of a seventh lawyer, Eaton. Then Claypool “repeatedly lied” to the inspector gneeral, denying that he asked to have the words “Marmer” and “ethics” removed from an invoice, Schuler wrote.

Schuler said Claypool told him, “I’m not looking at freaking bills.”