Headley spoke quietly while pleading guilty to the 12-count indictment. Security at the hearing was tight and included bomb dogs outside the courtroom.
Under the agreement reached with federal prosecutors, Headley will not be extradited to India, Denmark or Pakistan to stand trial on the Mumbai massacre. That agreement is expected to anger Indian authorities, who had been asking for access to Headley for interrogation and prosecution.
"His conduct contributed to the harm of many people," said Robert Seeder, Headley's attorney. After the hearing, Seeder said Headley has had "regret and remorse...from the day of his arrest became a cooperating individual."
The plea deal eliminates the possibility of the death penalty.
"The death penalty is off the table," said John Theis, Headley attorney. Theis said Headley will get a sentence of anything up to life. "He has agreed to be questioned by foreign governments in connection with overseas terror investigations, as long as they come to him."
According to the agreement, Headley must "fully and truthfully participate in any debriefings for the purpose of gathering intelligence or national security information, and Headley further agrees that, when directed by the United States Attorney's Office, he will fully and truthfully testify in any foreign judicial proceedings held in the United States by way of deposition, video-conferencing or letters rogatory."
Sentencing will be deferred until after Headley's finished cooperating.
U.S. Attorney Patrick Fitzgerald, who personally supervised the case, was in court for the plea bargain hearing, which lasted less than an hour.
Headley, 49, is a U. S. citizen of Pakistani descent. He admitted to helping to plan the November 2008 terrorist attacks in Mumbai that killed 164 people and wounded hundreds more. He also admitted to a second attack also in November 2008 on a Danish newspaper, a plan that included decapitating editors and throwing their heads out of windows.
Headley also admits to attending terror training camps in Pakistan between 2002 and 2005 and conducting surveillance for the Mumbai attacks.
Headley pleaded guilty to
Retired Cook County judge Ben Mackoff and his wife Carol were in the majestic Taj Mahal hotel that fateful day in November, 2008. They knew that terrorists were storming Mumbai, India because they heard the gunfire and saw three gunmen through the peephole of their hotel room door, where they would be captive for 42 hours.
"We didn't have time to be scared, we were just trying to survive," said Mackoff.What they didn't know was that a man from their hometown 8,100 miles away - David Headley of Chicago - had a guiding hand in the deadly assault.
Headley helped Pakistani terrorists select and scout targets in Mumbai.
"I want to make it clear that Mr. Headley was never involved in any kind of plot involving United States soil or United State's citizens," said Seeder.
Headley's co-defendant, Tahawwur Hussain Rana, has pleaded not guilty to similar terrorism charges.