Jason Dalton surprised judges and lawyers who expected him to fight the charges when he nearly immediately admitted to both murder and attempted murder.
Jason Dalton pleaded guilty to all counts of murder and attempted murder.
In March 2016, Dalton filed a $US10 million ($NZ14.8 million) federal civil rights lawsuit against the ride-sharing company after telling investigators that Uber's app had the ability to "take over" his body and compel him to kill.
The report said Dalton told officers he did not shoot when he was pulled over because the app went from black to red and "he felt like he was no longer being guided".
Dalton admitted to shooting Tiana Carruthers, 25, in a parking lot on February 20, 2016 - then admitted to gunning down father and son Rich, 53, and Tyler Smith, 17, later that night in a different parking lot.
Dalton had previously made weird outbursts in past court appearances, but was found competent to stand trial.
Jason Dalton talks with his defence attorney Eusebio Solis moments before pleading guilty to six counts of murder and several other charges at the Kalamazoo County Courthouse on Monday.
"I've thought about this quite a lot", he said to Lipsey. Prosecutors say he killed six people and injured two others across three locations.
Prosecutor Jeff Getting said the motive behind the shootings is a question that "haunts us".
"We're very happy that we're able to reach this resolution in the case", Getting said.
Getting said he was also shocked by Dalton's decision.
Dalton was an Uber driver at the time of the crimes and allegedly carried out the shootings in between picking up riders.
Families are scheduled to return to court for Dalton's sentencing on Tuesday, Feb. 5.
The 48-year-old told the judge Monday he wanted to plead guilty, avoiding a weekslong trial.