The school held a team meeting at noon EST Sunday to inform players of the decision to move on from Smith. The Fighting Illini suffered a 28-10 loss to Northwestern on Saturday to fall to 2-5 this season.
Illinois is scheduled to play an eighth game this week during Big Ten championship weekend. In a statement, the school said offensive coordinator Rod Smith will serve as interim head coach for the team's finale against Penn State on Saturday.
"Lovie Smith led the Illinois football program with unquestioned integrity during his nearly five years of service," Whitman said in a statement Sunday. "I have tremendous respect for Coach Smith and will always be grateful to him for providing a steady, experienced hand at a time when our program required stability. His unshakeable leadership, never more needed than during this pandemic, will be forever remembered.
"Nonetheless, based on extensive evaluation of the program's current state and future outlook, I have concluded the program is not progressing at the rate we should expect at this advanced stage in Coach Smith's tenure. To achieve our competitive objectives, I believe new leadership of the football program is required. I will always look fondly on the time Lovie and I have spent together. I wish him and MaryAnne nothing but the best."
The 62-year-old Smith posted a 17-39 record in his five seasons at Illinois, his first coaching job in college football since 1995. Before joining the Fighting Illini in March 2016, he had a lengthy NFL career that included head-coaching jobs with the Chicago Bears and Tampa Bay Buccaneers.
Smith led the Bears to a Super Bowl appearance in 2006 and went 81-63 with the franchise.
New York Giants assistant coach Bret Bielema, Buffalo's Lance Leipold, Army's Jeff Monken and Kent State's Sean Lewis are among those who are considered potential candidates to replace Smith at Illinois.