In 1989, Santos was appointed by newly-elected mayor Richard M. Daley as City Treasurer of Chicago.
[3] In 1991, after Santos raised alarm over the city's management of pension funds, mayor Richard M. Daley made an attempt to decrease her powers.
Santos' 1999 reelection came despite the fact that she was, at the time, under federal indictment for mail fraud and attempted extortion.
[3] However, Santos' conviction was overturned in 2000, and she was allowed to reclaim her elected position with back pay.
[3][5] However, six months later she again had to resign, as she pleaded guilty to a single count of mail fraud rather than facing retrial.