Jason Dalton pleaded guilty to all counts of murder and attempted murder.
He answered "yes" to a series of questions, admitting that he shot eight people at three locations.
Officials said he did not know the victims, and quoted Dalton as saying a "devil figure" on Uber's app was controlling him.
45-year-old Dalton entered the shock confession and subsequent guilty plea right on the cusp of a jury being selected for a fully-fledged trial of the case.
Jason Dalton was set to stand trial for fatally shooting four women in the parking lot of a Cracker Barrel restaurant, in addition to a father and son who were at a auto dealership, and for wounding two additional strangers.
Dalton will face a mandatory term of life in prison without the possibility of parole on the murder charges when he is sentenced next month.
In April 2016, a judge ruled that Dalton was mentally competent to stand trial after psychiatrists determined he understood the charges against him. Mary Lou Nye, 62, of Baroda, Michigan, was killed along with Dorothy Brown, 74; Barbara Hawthorne, 68, and Mary Jo Nye, 60, all of Battle Creek, Michigan.
Instead of heading to trial, Dalton pleaded guilty to killing Richard Smith, 53, and his son Tyler, 17, at a vehicle dealership.
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Charlie Flanagan, justice minister, said that the aim was to "positively exploit" opportunities in the legal sector after the United Kingdom leaves the EU.
"He either shook his head or said no, and I said, 'Are you sure?' " Derek continued.
Dalton was accused in the slaying of six people in Kalamazoo, Michigan, in 2016.
Prosecutor Jeff Getting said the motive behind the shootings is a question that "haunts us".
"Dalton proceeded to tell us that he couldn't imagine when he had bought them all that he would use them in this manner", according to the report.
"The report also showed there were more than 7.7 million property crimes previous year".
Dalton was an Uber driver at the time of the crimes and allegedly carried out the shootings in between picking up riders.
Dalton's sentencing hearing is scheduled for February 5, Brower told NPR.
The 48-year-old told the judge Monday he wanted to plead guilty, avoiding a weekslong trial.