On Twitter, user ElDonJuanDiaz posted: "George Zimmerman is a national hero. To you liberals and black people who believe everyone is racist keep crying."
Zimmerman's friend and former next-door neighbor, Jorge Rodriguez, said he always expected an acquittal.
"This is so far from being racial, it's not even funny," he told CNN's Chris Cuomo on "New Day."
"Just because he has a white last name and an African-American was dead, automatically everybody assumes racial. This is far from being race. This is just a bad situation that happened."
Tony Johnson, who is black, said he was disturbed by the "outbursts from people who didn't know the facts of the case, yet (were) still screaming about an injustice."
"I'm actually glad the verdict was not guilty," he told CNN's iReport. "Only based on the evidence that was presented in court, it screams self-defense.
"This wasn't about race," Johnson continued. "It was about a man's rights to defend himself. It's not a crime to follow anybody; therefore, the fact that they got into an altercation and George Zimmerman was forced to use deadly force, it's not a crime. Our Constitution states that."
Mark O'Mara, Zimmerman's defense attorney, said he was surprised by some of the protest.
"I'm a bit surprised that there is outrage because we had hoped that everybody would look at this case as being a very fair trial where both parties were represented well," he said.
Pushing for peace
Obama called for peace Sunday and acknowledged the Zimmerman case has stirred strong emotions.
"I now ask every American to respect the call for calm reflection from two parents who lost their young son. And as we do, we should ask ourselves if we're doing all we can to widen the circle of compassion and understanding in our own communities," he said.
"We should ask ourselves if we're doing all we can to stem the tide of gun violence that claims too many lives across this country on a daily basis," Obama said.
One critic of the verdict, Terri Weems, said the trial was a referendum on race that confirmed what she said Martin supporters knew all along.
"That's our society," she said as she headed into church in Washington on Sunday. "We expected not to be given justice. We haven't been dealt justice all this time. ... It's very disheartening."
NAACP President Benjamin Jealous said on CNN's "State of the Union" on Sunday that the largely peaceful nature of the protests is a positive sign.
"I think we should, frankly, right now be celebrating the fact that we've seen a generation of young people respond by using our system, raising their voices, but not using their fists," he said.