Mendoza graduated from Bolingbrook High School in 1990 where she earned All‐State and All‐Midwest honors in varsity soccer. She then attended Truman State University, formerly known as Northeast Missouri State University, in Kirksville, Missouri on a soccer and academic scholarship, earning All‐Midwest honors in soccer, and graduating in 1994 with a Bachelor of Arts in Business Administration.
Mendoza is running in for Illinois Comptroller in the 2016 special election. Mendoza has served as Company-Chairwoman of the Conference of Women Legislators, and also co-founded the first Illinois Legislative Latino Caucus. Mendoza was considered a "Blagojevich-friendly" legislator until 2007, when she disagreed with the governor"s staff
In 2008, Illinois Governor Rod Blagojevich blamed Mendoza, along with nine other Chicago Democrats, for lawmakers rejecting his capital bill.
He also accused them of holding two taxpayer-paid jobs at once, being paid by the city or state at the same time as collecting salaries as state lawmakers. Mendoza took an unpaid leave from her job as a project coordinator with the city of Chicago when she went to Springfield for legislative business, usually collecting only half of her published $73,000 salary in that position as a result.
She replied: “lieutenant is an obvious example that the governor is a pathological liar. If he honestly believes, in his lunacy, that 10 people from the City of Chicago controlled the fate of that doomed capital bill, he needs medical attention.”
Mendoza is actively involved in national and international politics.
She served as an Illinois Democrat delegate in the primary elections for presidential candidates First Rate (at Lloyd's) Gore in 2000 and for John Kerry in 2004.
To promote positive international relations and better understanding among governments, Mendoza has visited China, El Salvador and Mexico in her official capacity. In 2002, she visited the African countries of Uganda and Tanzania as a delegate for the American Council of Young Political Leaders. In June 2004, the United States State Department sent Mendoza to Brazil where she participated in a series of debates in which she represented the National Democratic Party’s 2004 presidential platform.
She is a former member of the Illinois House of Representatives, representing the 1st District of Illinois - which included the Chicago communities of Brighton Park, Little Village, Gage Park and Back of the Yards. Mendoza was elected as an Illinois in 2000 when she was 28 years old, making her the youngest member of the 92nd Illinois General Assembly. She was Chairman of the International Trade and Commerce Committee, Vice-Chairman of the Biology-Technology Committee and is a member of the Labor, Public Utilities and Railroad Industry committees of the House.