Manning was sentenced Wednesday to 3 1/2 decades behind bars for giving more than 700,000 secret U.S. files to WikiLeaks.
The sentence was considerably less than the 60 years sought by prosecutors, but more than the 25-year sentence sought by defense lawyers.
Defense attorney David Coombs, speaking to reporters after the sentence, said in "any sentence of more than 30 years, the individual will be eligible for parole after 10." With credit for time served, parole could come in seven years, he said.
Sometimes calling his client "Brad," Coombs said, "I do believe he's the type of person who couldn't live with himself if he didn't do something" about the confidential files that sometimes embarrassed the United States and its allies, and revealed secret military information.
Coombs said statements by President Obama were not grounds for an appeal, but, "I do think those statements had an impact." The lawyer said he would ask Obama for a presidential pardon next week.
Earlier in the case, Obama said, "We are a nation of laws. We don't let individuals make decisions about how the law operates. He [Manning] broke the law."
Coombs also objected to Manning's dishonorable discharge. "I can see a bad conduct discharge, but not a dishonorable," he said. "Bradley Manning is a man of honor.
Army Col. Denise Lind, the military judge in the Fort Meade, Md., courtroom, sentenced Manning to forfeiture of all pay and benefits in addition to the prison term and dishonorable discharge.
There initially was no audible reaction to the sentence from the 45 people allowed in the courtroom, and Manning exhibited no visible reaction to the sentence, NBC News reported. Guards quickly moved Manning from the courtroom as Lind left and supporters began yelling: "You're our hero!" and "We'll keep fighting for you, Bradley!" NBC reported.
Prosecutor Capt. Joe Morrow asked for 60 years, arguing Manning endangered lives and hurt diplomatic relations critical to national security. Defense attorney David Coombs asked Lind to be lenient and allow Manning a chance to rehabilitate himself.
Coombs said the leaks, however large, had not been proved to be a long-term threat to U.S. security.
"Long after this information probably is no longer even classified -- if it's still classified -- long after that day has passed, the government still wants Pfc. Manning rotting in a jail cell," Coombs said Monday.
Manning avoided a life sentence when Lind acquitted him of the most serious charge, aiding the enemy.
Coombs is expected to appeal Manning's sentence to the Army Court of Criminal Appeals, which reviews certain court-martial convictions.
An appeal after that would go to the U.S. Court of Appeals for the Armed Forces, composed of five civilian judges appointed by the president and confirmed by the Senate.
Coombs said last month he thought it was possible the case could end up in the U.S. Supreme Court, Manning supporters said.
Manning, 25, pleaded guilty Feb. 28 to 10 lesser charges for being WikiLeaks' source for the material, which included videos of a 2007 Baghdad airstrike and a 2009 airstrike in Afghanistan in which civilians were killed. The leaked information also included 250,000 U.S. diplomatic cables and 500,000 Army reports that came to be known as the Iraq War logs and Afghan War logs.
The disclosures were the largest set of restricted documents ever leaked to the public -- much of it published by WikiLeaks or its media partners from April to November 2010.