The victim was killed in a robbery attempt outside a restaurant. Reportedly, he had gone there to pick up food for a family party.
Jackson spoke at the service during which Elliott was praised as a husband of 54 years and a caring member of his church.
"Today is a day for remembering the life of a special man who worked for the state of Illinois, devoted his life to helping other people-- both in job and in his community and in his church. And I'm only here as another person in Illinois to pay my respects to a great man," said Jackson.
The alleged gunman, 48-year-old Lee Cration of Joliet was on parole after a 1985 murder conviction. He's being held in Cook County jail without bond on charges of first-degree murder, armed robbery, and parole violation.