It happened November 17 on Interstate 74 near mile marker 94 in East Peoria.
The victim is 48-year-old Jonathan Hicks.
Peoria County Coroner Johnna Ingersoll said Sunday Hicks was the sole occupant and operator of a motorcycle headed eastbound on the interstate when he rear-ended another vehicle.
Ingersoll said the impact threw Hicks off, resulting in multiple injuries to his body, including his head.
Hicks remained hospitalized at OSF St. Francis Medical Center in Peoria ever since the crash.
Ingersoll said his condition never improved. Hicks was pronounced dead Saturday.
No autopsy is planned, but toxicology test results are pending.