Jim Rosendall's cooperation with the FBI led prosecutors to recommend a sentence of no more than 11 months in prison, well below the five-year maximum.
The company used cash and plane trips to Las Vegas to curry favor with Detroit officials and win the $47 million contract to recycle sludge, according to a criminal charge unsealed earlier in the day.
The city officials were not identified.
The influence-peddling game reached a climax in fall 2007 when a city council member accepted payments to vote in favor of a deal with Synagro Technologies, the government alleges. The contract was approved, 5-4, in November 2007.
"People expected me to give things to get their support," Rosendall, former president of Synagro of Michigan, said in court.
Earlier Monday, Mayor Ken Cockrel Jr. addressed speculation about a federal investigation into the conduct of city government members. "I think we'll have to see how it plays out," he said.
Rosendall's guilty plea comes more than four months after Kwame Kilpatrick resigned as mayor and went to jail in a sex-and-text scandal after admitting he lied during a civil trial to cover up a torrid affair with his chief of staff.