A Democrat, Giannoulias defeated Republican State Senator Christine Radogno with 54 percent of the vote in the November 2006 election for Illinois Treasurer.

[1] Giannoulias served on the board of directors of the Community Banker's Association of Illinois Legislative Committee, the South Side/Wabash YMCA, and the Edgewater Chamber of Commerce.

Giannoulias also founded and chaired the AG Foundation, a not-for-profit charity that donated money to treat child-related illnesses, curb poverty and assist disaster relief organizations.

[4] Although the state Democratic Party led by House Speaker Mike Madigan backed his opponent, Paul Mangieri, in the primary, Giannoulias was endorsed by U.S.

[6][7] The Chicago Sun-Times news group also endorsed Giannoulias in the general election, arguing that he would "bring valuable private enterprise experience from banking to the job" and praising his "creative" policy proposals like a securities lending program, improving Bright Start, and promoting green energy.

[8] Running on a campaign platform that emphasized comprehensive ethics reform for the Treasurer's office,[9] Giannoulias won the March 2006 primary and went on to defeat Republican candidate Christine Radogno in the general election.

[10][11] In 2009, Giannoulias worked to encourage Wells Fargo to cooperate in the sale of Chicago-based clothing manufacturer Hartmarx Corp., which was at risk of liquidation and had filed for Chapter 11 protection.

[12] Wells Fargo, a primary lender for Hartmarx, is also "the money custodian for the treasurer's office, holding its cash and other financial assets."

"[13] Giannoulias cited the fact that Wells Fargo received over $25 billion in federal TARP bailout funds as further reason why the bank should have supported the sale of Hartmarx instead of pursuing the company's liquidation.

"[14] Giannoulias launched the "Green Rewards" program, which gives a $1,000 rebate to Illinois residents who purchase a new hybrid or other fuel-efficient vehicle.

Giannoulias said: "This is a good way to safely diversify our portfolio, especially during a time when some of our other investment options aren't generating as much revenue because of the market fluctuations here in the United States.

The Fallen Heroes Scholarship Program, which Giannoulias designed in a partnership with the Illinois Department of Veterans Affairs, awards an initial investment of $2,500 in college savings to children who have lost a parent in military service since 2001.

"[24] In 2009, Oregon,[28] Nebraska,[29] New Mexico, Texas, Maine and Illinois[30] all investigated OppenheimerFunds' handling of their college savings programs for impermissible investments and misconduct.

[24] In January 2009, at the request of Giannoulias, the Illinois Attorney General initiated its own probe of OppenheimerFunds, issuing subpoenas on the company.

"[27] Despite the problem associated with OppenheimerFunds' handling of Core Plus, Bright Start remains a highly regarded 529 college savings program.

In April 2009, Consumer Reports studied college savings programs across the country "to see how well they performed during last year's stock-market plunge.

"[33] Consumer Reports "found five that are worthy of an A," and ranked Bright Start as one of the top five college savings programs in the nation.

[40] Giannoulias started a pilot program in 2007 to sell the abandoned contents of safe deposit boxes on eBay, scrapping the state's annual live auctions.

[43] Broadway Bank's struggling financial situation is due to delinquent real estate loans and foreclosed properties.

Broadway Bank made these loans before Rezko was investigated, indicted, or convicted for any crimes, but not before the criminal conduct took place.

[38] Broadway Bank also loaned money for real estate developments to Michael Giorango, who has been convicted for prostitution and bookmaking.

[52] On March 2, 2009, Giannoulias stated on CNBC that he was forming an exploratory committee in order to assess a potential candidacy for the US Senate in 2010.

[53] Giannoulias was endorsed by Planned Parenthood, the Service Employees International Union (SEIU), AFSCME, the AFL–CIO, the League of Conservation Voters, the Human Rights Campaign, the Chicago Sun-Times, and the Sierra Club (Planned Parenthood, the League of Conservation Voters, and the Human Rights Campaign had all supported Rep. Mark Kirk, Giannoulias' Republican opponent, in previous races).

[59] On November 2, 2010, Kirk defeated Giannoulias for Illinois' open United States Senate seat by a margin of 2%.