With 46 percent of the vote, billionaire J.B. Pritzker beat out a crowded field of Democrats for the nomination for governor.
The Hyatt hotel heir contributed $69.5 million to his own campaign, helping propel him to victory over five other candidates, including Chris Kennedy and state Sen. Daniel Biss.
In his victory speech, Pritzker took aim at Republican Gov. Bruce Rauner.
"I’ve had enough of people like Donald Trump, politicians like Bruce Rauner who can never acknowledge a flaw, never offer an apology and never take responsibility for anything or anyone under their care,” he told a crowd at a Marriott Hotel in downtown Chicago.
The first-term governor squeezed out a primary win over state Rep. Jeanne Ives, winning by 4 percentage points.
"The election in November will be a choice, a clear choice. A choice between someone who will stand up to the machine and someone who will long be part of it," Rauner said in his victory speech.
In another statewide race, Erika Harold was declared the winner in the GOP primary for attorney general. She defeated Gary Grasso, a DuPage County Board member.
State Sen. Kwame Raoul won the eight-way Democratic race for the state's top lawyer, edging out former Gov. Pat Quinn by 2 percentage points.