Troutman could face up to five years in prison when she is sentenced later this year.
Wednesday's guilty plea by Troutman contradicts earlier claims by the former alderman that she was innocent of the corruption charges.
Troutman was soft spoken in court when she answered "yes" to the judge's question of whether she had accepted illegal cash payments. It's an about-face from the adamant declarations of innocence when she was first indicted last year.
If she had gone to trial, she could have been sentenced to 23 years.
Troutman remained quiet as she left the federal courthouse Wednesday afternoon. She was barely audible moments earlier as she stood in a courtroom and pleaded guilty to taking payoff money and cheating on her taxes.
"For the benefit of her family and the benefit of her personally, we thought this was the best thing to do at this time," said Sam Adam, Jr., Troutman's attorney.
Her attorney emphatically denied any wrongdoing on his client's behalf when the former 20th Ward alderman was first accused a year and a half ago of taking bribes from real estate developers.
An FBI investigation led agents to raid both her South Side home and aldermanic office in January of 2007. She was ultimately charged in a 13-count indictment but pleaded guilty to two counts - mail fraud and tax fraud. The other 11 counts were thrown out.
Troutman's attorney says despite the plea deal, she has an impeccable record.
"A young woman who started off in the coal fields in West Virginia and worked her way up to become a 17-year alderman," said Adam.
Troutman was set to go to trial next month.
Dan Sprehe, with the Better Government Association, says changing her plea was a "smart maneuver."
"Generally, if you take a plea agreement, you are saving the government a good deal of time and effort in bringing you to trial," he said.
Two of Troutman's associates were also indicted and will stand trial in the next few months. Troutman's attorney says her plea deal does not mean she's cooperating with the government against anyone else in the ongoing investigation, just that she wants to put the case behind her.
She will be sentenced in December.
