Tahawwur Rana, an accomplice of Mumbai attack terrorist David Headley, was sentenced to 14 years in jail followed by five years of supervised release for the "serious crime" of providing material support to Pakistan-based LeT and for backing a plot to strike a Danish newspaper.
The US District Judge Harry D Leinenweber gave his order after hearing from both the government attorney and those of 52-year-old Rana, during which the two argued on the length of imprisonment.
The last minute arguments lasted for more than an hour and half.
The Defence had sought a lighter sentence of about nine years citing Rana's poor health while the Prosecution wanted a 30-year jail term.
"Based upon presiding over the trial and reading over the material that has been provided to me, we have on one hand a very intelligent person capable and willing to provide assistance to many many people.
"What is difficult to understand how that kind of person is sucked into a ghastly plot that was proposed to go into the private office of a newspaper.
"We find that Rana got involved in this action which would have provided death and injury to a number of people. Fortunately it was stopped prior to being carried out," the judge said.
He added: "It seems to me that people who are determined to carry out terrorist activity really do not care about what is going to happen to them. As long as Rana is in custody he is personally deterred from any personal such activity.
"Providing a long sentence would make sure that Rana does not get involved in any kind of terrorist activity in the future".