Loomis identified the officers as Wilfredo Diaz, Brian Sabolik, Erin O'Donnell, Michael Farley, Chris Ereg and Michael Brelo.
Police in a tweet Tuesday said six other officers were suspended without pay for up to a month and a 13th officer retired last year.
Loomis, a veteran of 23 years, vowed to get the fired officers' jobs back. There is "no rhyme or reason" to the dismissals, and he said he and other officers are scratching their heads because the firings seem random, as if names were picked out of a hat.
"This is nothing but politics. I have every confidence in the world we're going to get their jobs back. I'm not going to stand for it," Loomis said.
How, he asked, can the six officers be fired when a grand jury opted not to indict 12 of the 13 officers and the sole remaining officer, Brelo, was acquitted by Cuyahoga County Judge John P. O'Donnell?
In his May 2015 decision, O'Donnell ruled that Brelo's use of force was permissible because he had reason to believe he was threatened. And it couldn't be proved that Brelo's shots were the fatal ones, so the judge couldn't issue a guilty verdict on the manslaughter charge, he said.
'I don't trust police'
After the verdict, protesters outside the courthouse chanted, "No justice, no peace," a slogan popularized during the Michael Brown protests in Ferguson, Missouri, and the Eric Garner protests in New York.
The protests were largely peaceful, though at least 71 people were arrested that weekend for offenses including felonious assault, aggravated rioting, unlawful congregation and failure to disperse, police Chief Calvin Williams said.
Russell's and Williams' family members also frowned on the verdict.
"All I know is that I don't trust police no more. No police. None," Williams' brother, Alfredo Williams, said. "I can't recover from this. ...This verdict isn't real. This verdict is fake."
Loomis informed CNN of the firings as high-ranking police and city officials held a news conference regarding the 22-mile chase. During the chase, there were 46 supervisors on duty, 18 of whom were involved in the pursuit, said police Cmdr. James Chura, calling the incident unprecedented. Of those supervisors, one was terminated, two were demoted and nine were suspended for from three to 30 days.
As for the 105 officers involved in the pursuit, 63 were suspended for between one and 10 days, he said.
"We said we would conduct a fair process, and I believe we have done that," Mayor Frank Jackson said. "They will feel however they feel, but we conducted this in a fair way, with due process."
What happened that night?
The chase started the night of November 29, 2012, when a couple in a car sped away from an undercover officer.
Their engine backfired, sputtering and producing a loud bang in the tailpipe. Prosecutors said officers mistook the noise for gunshots, and a high-speed chase ensued.
Investigators said as many as 62 police cars joined at speeds of up to 100 mph through the streets of Cleveland.
After the chase, Russell rammed a police car in a middle school parking lot, police said.
That's when the bullets started flying.
An investigation revealed 13 police officers fired more than 100 times in eight seconds.
Brelo got out of his police car, climbed atop the hood of Russell's car and "fired at least 15 shots ... downward through the windshield into the victims at close range as he stood on the hood of Mr. Russell's car," Cuyahoga County Prosecutor Timothy McGlinty said.
Brelo told investigators he thought he and his partner were in danger, believing the couple in the car were shooting.
"I've never been so afraid in my life," the former Marine told investigators. "I thought my partner and I would be shot and that we were going to be killed, at which point I drew my weapon and I shot through the windshield at the suspects."
Russell and Williams were both homeless with a history of mental illness and drug use, according to Ohio's Bureau of Criminal Investigations
. Witnesses said they were most likely looking to buy drugs that night. A police officer ran a license plate check of the 1979 Chevy Malibu that Russell was driving. He had gotten it from a relative, and the check came back clean.
Still, the officer tried to pull him over for a turn signal violation. Russell then sped away.