Daniel Pantaleo has four months to appeal his firing from the NYPD in court.  

"A decision like this is extremely difficult to overturn," said Rae Koshetz.

Koshetz, an attorney, spent 14 years as the NYPD's Deputy Commissioner for Trials. She played a key role in the last firing of an NYPD officer for a chokehold, until Pantaleo was dismissed Monday.

"I presided over the Francis Livoti case," Koshetz said.

Livoti was the NYPD officer who was fired, and later convicted in federal court, for placing Anthony Baez in a fatal chokehold in the Bronx back in 1994.

Both the U.S. Justice Department and a Staten Island grand jury declined to bring criminal charges against Pantaleo.

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But Koshetz says the police commissioner's dismissal of the officer, following the recommendation of the deputy commissioner who heard testimony, appears to be legally solid.

"It looks to me here as though…the disciplinary decision was well reasoned and very detailed," Koshetz said.

There have been cases of officers successfully suing to get their jobs and pensions back after being fired for breaking NYPD Patrol guidelines. But those outcomes are very rare.

Stuart London, Pantaleo's defense lawyer, says he will try to prove Pantaleo's punishment doesn't fit the offense of using a banned chokehold, and that the NYPD initially told the union Pantaleo would not be fired but allowed to resign with a pension and health benefits for the rest of his life.

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"He did everything right except for three or four seconds. So we will focus on that," London said Monday. "We will also focus on de Blasio's involvement, indicating we are going to get justice for the Garner family."

In Pantaleo's situation, Eric Garner died during the encounter with police. That will make overturning his dismissal nearly impossible, according to experts.

"A court would have to find that there was a gross abuse of discretion on the part of the police commissioner," Koshetz said. "Just from what I know about the case, I don't see that here."

Since Pantaleo's firing, financial support is growing; a GoFundMe page set up for him has increased by tens of thousands of dollars. Meanwhile, supporters of Garner have started a petition to get that Pantaleo GoFundMe page shut down.