Teixeira, 22, agreed to plead guilty in March to six counts of willful retention and transmission of national defense information. In exchange for his guilty plea, the Department of Justice agreed to not charge Teixeira with Espionage Act violations. The plea agreement stipulated that Teixeira be imprisoned for between 11 years and 16 years and eight months, pay a $50,000 fine, and serve 36 months of supervised release following his prison term.

Judge Indira Talwani issued the 15-year sentence at a Nov. 12 court hearing.

Teixeira offered an apology before being sentenced.

"I wanted to say I'm sorry for all the harm that I brought and caused," Texeira said.

"I understand all the responsibility and consequences fall upon my shoulders alone and accept whatever that will bring," he added.