Prosecutors said Cecil Suwal, 23, ran the day-to-day operations of the Emperors Club V.I.P. escort service, which charged clients up to $5,500 an hour for the services of its women.
Suwal was accused of supervising the company's booking agents, paying out hundreds of thousands of dollars to prostitutes and controlling shell companies used to hide the ring's profits.
"This is the first step in the process of putting this chapter of her life behind her," her lawyer, Alberto Ebanks, said before the plea in U.S. District Court. "She deeply regrets her actions. She is remorseful. She is contrite and she is determined to right her wrongs in a manner that is fair and just."
A former University of Miami student who graduated from the prestigious Blair Academy in New Jersey, Suwal got her job at the Emperors Club after answering a help wanted ad. She later moved in with the man accused of founding the service, Mark Brener. The couple lived in an apartment complex in Cliffside Park, N.J.
Brener, 62, has pleaded not guilty and is awaiting trial.
Suwal is the second person to plead guilty in the case. Temeka Lewis, a booking agent for the escort service, pleaded guilty to similar charges in May.
Spitzer hasn't been charged in the case, but he apologized and resigned on March 12, shortly after the case became public.
During the investigation, which began with an inquiry into suspicious cash transfers, federal agents listened in on Spitzer's telephone calls and analyzed his bank records. Prosecutors have declined to say whether they intend to charge him with breaking any laws.