It was at this time, while working a full-time job, that she became a local community organizer for her neighborhood and got involved in Chicago politics.

Central to the mayor's aggressive development plans, the First Ward election was one of five hotly contested races in independent efforts to oppose the city's patronage political system.

Granato's chief support came from then-Mayor Richard M. Daley as well as the controversial Hispanic Democratic Organization and Coalition for Better Government.

In 1998, Mendoza was slated by the regular Democratic Organization but lost to independent progressive incumbent Sonia Silva (1st Legislative District).

[9] In 2000, immediately after her victory for Granato and supported by Daley, the Hispanic Democratic Organization, and House Speaker Michael Madigan,[10][11] Mendoza was slated and elected as an Illinois State Representative.

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.

"[14] Mendoza served as an Illinois Democratic delegate in the primary elections for presidential candidates Al Gore in 2000 and John Kerry in 2004.

[15] In 2002, she visited the African countries of Uganda and Tanzania as a delegate for the American Council of Young Political Leaders.

[16] In June 2004, the 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.

[20] Mendoza ran for Illinois Comptroller in the 2016 special election, defeating the Republican incumbent Leslie Munger by 5% of the votes cast.

[27] Her second year in office, she passed[clarification needed]| three more Transparency bills: 1) The Truth-in-Hiring Act (requiring governors to list employees on their own payroll), 2) The Truth in Budgeting Act (requiring governors to address the state's Late Payment Interest Penalties in their proposed budgets) and 3) The Vendor Payment Program Transparency Act (requiring lenders to state vendors to disclose their owners and the source of their financing).

[citation needed] In 2018, Mendoza was re-elected as comptroller, winning 59.9% of the vote in an election against Republican nominee Darlene Senger.

The statement brought up a scandal involving allegations of sexual misconduct that had been lodged against Preckwinkle's former chief of staff.

[3] She serves on the board of advisors of Let America Vote, an organization founded by former Missouri Secretary of State Jason Kander that aims to end voter suppression.