The governor is reducing the sentence to 10 years for Rogel Aguilera-Mederos.
Polis says Aguilera-Mederos will be eligible for parole in five years, starting Dec. 30, 2026.
"The length of your 110-year sentence is simply not commensurate with your actions, nor with penalties handed down to others for similar crimes," Polis wrote in a commutation letter to the driver. "There is an urgency to remedy this unjust sentence and restore confidence in the uniformity and fairness of our criminal justice system, and consequently I have chosen to commute your sentence now."
See copies here of the governor's executive orders and letters of commutation issued Thursday for this case and others.
A petition on change.org for Aguilera-Mederos urges that his sentence be lowered, commuted for time served or that he be granted clemency.
Authorities at the time of sentencing said the term was the mandatory minimum set by law, but a prosecutor already filed a motion for the sentence to be reconsidered.
A hearing on reconsideration was scheduled for next month, but may be unnecessary given the governor's actions Thursday.
In April 2019, Aguilera-Mederos was driving a semi tractor-trailer, traveling at 85 mph, when the brakes failed, he told investigators at the time. He tried to pull over to the shoulder to avoid stopped traffic, but another semi had already stopped there, according to an arrest affidavit.
This resulted in a fiery 28-car pileup that killed four people on a highway in Denver.
The crash killed 24-year-old Miguel Angel Lamas Arellano, 67-year-old William Bailey, 61-year-old Doyle Harrison and 69-year-old Stanley Politano.
Relatives of victims said at Aguilera-Mederos' sentencing he should serve time for the crimes.
Aguilera-Mederos was sentenced last week after the 26-year-old was found guilty in October and convicted on vehicular homicide and 23 other charges.
MORE | Truck driver sentenced to 110 years in prison in deadly 28-car pileup in Colorado
The other 23 charges included six counts of assault in the first degree -- extreme indifference; 10 counts of attempt to commit assault in the first degree -- extreme indifference; two counts of vehicular assault -- reckless; one count of reckless driving; and four counts of careless driving causing death.
Legal experts say because Colorado did away with the death penalty, life in prison is the harshest punishment possible.
"Once you have 23 felonies with mandatory minimums that are served consecutively, that can quickly add up," explained Ian Farrell, a law professor at the Sturm College of Law - University of Denver.
In imposing the sentence, District Court Judge Bruce Jones said it was the mandatory minimum term set forth under state law - and suggested a lesser punishment was warranted. Mandatory minimum sentencing laws required that sentences on 27 counts of vehicular assault, assault, reckless driving and other charges run consecutively.
"I will state that if I had the discretion, it would not be my sentence," the judge said.
The change.org petition, which is titled "Offer commutation as time served, or grant clemency to Rogel Lazaro Aguilera-Mederos, 23" was created by a woman from Colorado who claims she has no relation to Aguilera-Mederos and is simply a supporter, according to the website.
"I made this petition because I am a native to Colorado, who believes this man is NOT a criminal and this was purely an accident," she wrote on a status update on Dec. 15. "I'm not related to Rogel, or any of his family, I simply believe that he doesn't deserve his sentence or these charges."
The petition goes on to say, "Rogel has said several times that he wishes he had the courage to crash and take his own life that day, this tragic accident wasn't done with Intent, it wasn't a criminal act, it was an accident."
ABC News, the Associated Press and CNN contributed to this report.