In December 2008, then-Democratic Governor of Illinois Rod Blagojevich and his Chief of Staff John Harris were charged with corruption by federal prosecutor Patrick Fitzgerald. As a result, Blagojevich was impeached by the Illinois General Assembly and removed from office by the Illinois Senate in January 2009. The federal investigation continued after his removal from office, and he was indicted on corruption charges in April of that year. The jury found Blagojevich guilty of one charge of making false statements with a mistrial being declared on the other 23 counts due to a hung jury after 14 days of jury deliberation. On June 27, 2011, after a retrial, Blagojevich was found guilty of 17 charges (including wire fraud, attempted extortion, and conspiracy to solicit bribes), not guilty on one charge and the jury deadlocked after 10 days of deliberation on the two remaining charges. On December 7, 2011, Blagojevich was sentenced to 14 years in prison.The investigation became public knowledge when a federal judge revealed that Blagojevich was the "Public Official A" in the indictment of Tony Rezko. The case gained widespread attention with the simultaneous arrests of Blagojevich and Harris on the morning of December 9, 2008 at their homes by federal agents. Blagojevich and Harris were each charged with one count of conspiracy to commit mail and wire fraud and one count of soliciting bribes. The case involved sweeping pay to play and influence peddling allegations, including the alleged solicitation of personal benefit in exchange for an appointment to the U.S. Senate as a replacement for Barack Obama, who had resigned after being elected U.S. President (see bribery). U.S. Attorney Patrick Fitzgerald noted that there had been no evidence of wrongdoing by Obama.After the arrest, Illinois elected officials began calling on Blagojevich to resign. The 50 members of the U.S. Senate's Democratic caucus called on Blagojevich to not appoint a senator and pledged not to seat anyone he attempted to appoint. Legislators introduced bills in both houses of the Illinois General Assembly to remove the Governor's power to appoint a senator and require a special election; however, no such bill passed. Blagojevich did eventually appoint Roland Burris to the seat. Despite attempts to keep Burris from taking the seat in the U.S. Senate, he was eventually allowed to take the oath of office. Within days of Blagojevich's arrest, Illinois Attorney General Lisa Madigan filed a motion with the Illinois Supreme Court seeking to declare the Governor "unable to serve" and strip him of the powers of his office. The court denied the request. Meanwhile, Illinois House Speaker Mike Madigan (the Attorney General's father) announced that on December 16 he would begin impeachment proceedings. The state House impeached Blagojevich on January 9, 2009, and the state Senate convicted him 20 days later, thereby removing him; they also disqualified him from holding further office in the state.

The governor of Illinois is the head of government of Illinois, and the various agencies and departments over which the officer has jurisdiction, as prescribed in the state constitution. It is a directly elected position, votes being cast by popular suffrage of residents of the state. The governor is responsible for enacting laws passed by the Illinois General Assembly. Illinois is one of 14 states that does not have a gubernatorial term-limit along with Connecticut, Idaho, Iowa, Massachusetts, Minnesota, New York, North Dakota, Texas, Utah, Washington, Wisconsin, District of Columbia, Vermont, New Hampshire and Puerto Rico. The governor is commander-in-chief of the state's land, air and sea forces when they are in state service.

The 43rd and current governor is J. B. Pritzker, a Democrat who took office on January 14, 2019.