In total, Manning has been found guilty of 17 out of the 22 counts against him in their entirety, and guilty of four more counts in an amended version.
US soldier Manning was arrested in Iraq in May 2010 on suspicion of passing over classified documents to WikiLeaks.
A statement from the Manning family given to The Guardian read as follows: "While we are obviously disappointed in today's verdicts, we are happy that Judge Lind agreed with us that Brad never intended to help America's enemies in any way.
"Brad loves his country and was proud to wear its uniform."
Manning, 25, had already pleaded to 11 of 22 charges after military judge Colonel Denise Lind ruled against a public interest defence for his leaks.
His bid to have the "aiding the enemy" charge dismissed had been rejected, with the judge ruling that Manning's training meant that he was aware his public release of information could threaten US national security.
An eight-week court martial headed by Lind was held in Fort Meade, Md.
Manning could yet face years in prison without parole. The charges to which he had already previously pleaded guilty carried a maximum sentence of 20 years in prison.
His lawyer David Coombs has pledged to call several witnesses in the sentencing segment of proceedings, and a lengthy sentence is likely to be appealed.