Circuit Judge Debra Nelson, sitting in Sanford -- where Martin, an unarmed black teenager, was shot -- said Zimmerman could not prove NBC acted with reckless disregard for the truth in its reporting on the case. NBC dismissed two employees involved in editing the two news segments on Zimmerman that were the subject of the lawsuit.
"There exists absolutely no clear and convincing evidence that defendants knew that the information published was false at the time it was published, or recklessly disregarded the truth or falsity of those statements," Nelson said.
Zimmerman charged that one segment about his 911 call the night of the shooting was edited so that he appeared to be involved in racial profiling and to have told Sanford police Martin was black. He said that in another segment, NBC said he had used a racial slur.
The network has publicly apologized for its reporting on the case.
Nelson, in a 15-page order, said that NBC frequently quoted Zimmerman's relatives and friends, who said he was not a racist. She said he had been a public figure since 2010, when he protested the slow response by Sanford Police to an incident where a white officer's son broke the nose of a black homeless man.
Martin, 17, of Miami Gardens was shot in February 2012 as he walked to a relative's house in a gated community in Sanford.
Zimmerman, a Neighborhood Watch volunteer who said he shot Martin after the teenager attacked him, was acquitted of killing Martin.
Critics said that if Martin did assault Zimmerman it was because he was afraid of an unknown man following him. The 911 dispatcher urged Zimmerman to back off and wait for police.
Zimmerman can appeal Nelson's ruling.