Doug House, president of the Illinois Democratic Chairmen's Association, is endorsing J.B. Pritzker for governor.
House's endorsement comes as the chairmen's association is prepared to vote next month on an endorsement in the primary. House also chairs the Rock Island County Democrats.
House's announcement comes about a week after Pritzker and several other candidates for the Democratic nomination appeared at the county party's annual Salute to Labor picnic.
House praised Pritzker's temperament, organizational skills and his stand on a range of issues, including health care.
"His message is resonating," House said, "and people are drawn to it."
The Illinois governor's race is significant for the Democratic Party not only in the state but nationwide, House said, in order to show the party is not just resonant on the coasts. And he said Pritzker is most capable of beating incumbent Gov. Bruce Rauner.
"I just think that J.B. Pritzker is the superior candidate," House said.
Pritzker, a wealthy Chicago entrepreneur, is one of a handful of Democrats seeking the party's nomination.
Also running are state Sen. Daniel Biss, D-Evansdale, businessman Chris Kennedy, Chicago Alderman Ameya Pawar, state Rep. Scott Drury, D-Highwood, Madison County regional schools superintendent Bob Daiber and Tio Hardiman, a community organizer in Chicago.
Pritzker, Biss, Kennedy and Daiber were at the Rock Island County Labor Day picnic.
The state county chairmen's group is scheduled to vote next month on an endorsement.