On Friday, the world learned more about Zimmerman as he, his wife and parents testified during a hearing in Sanford, Florida, to decide whether he would be released on bond while awaiting trial on a second-degree murder charge in the February 26 death of Trayvon Martin.
Zimmerman's wife depicted him as a man she has never seen angry. His father said he was a truthful man who had long been concerned with helping others. And his mother said he had organized a campaign to "get justice" for a homeless man who had been beaten in Sanford, as well as mentoring a 14-year-old African-American boy from a dangerous Orlando neighborhood.
Zimmerman has acknowledged killing Martin during an encounter in his Sanford neighborhood, saying he shot in self-defense. Critics have depicted the Hispanic neighborhood watch officer as a racist who profiled Martin because he was African-American.
His family said nothing could be further from the truth.
"I know that he is very protective of people, very protective of homeless people and also of children" -- regardless of their race, Gladys Zimmerman said in testimony meant to prove to Judge Kenneth Lester Jr. that Zimmerman would not be a threat to the community if allowed to leave jail while awaiting trial.
She said he has been a mentoring the 14-year-old for three years even though the program he had joined shut down after only nine months because of the economy.
She said she begged him not to go because of the danger.
"He said, 'Mom, if I don't go, they don't have nobody,'" Gladys Zimmerman said.
She said her son also participated in a 2010 campaign to "get justice" for an African-American homeless man who was seen in a videotape taken by an onlooker being struck by a man who later turned out to be the son of a Sanford police lieutenant.
"He went to churches. He put fliers on cars" and organized a meeting seeking help for the man, his mother testified.
He was recognized by the city for his efforts, his mother said.
CNN has not been able to confirm Zimmerman's participation in the campaign.
Zimmerman was studying criminal justice and wanted someday to be a judge or a magistrate, said his father, Robert Zimmerman Sr. -- who had also been a magistrate.
"He's always been concerned about people in society, so he wanted to be able to help somehow," the elder Zimmerman said.
Prosecutors sought to paint a darker picture of Zimmerman as a man with a violent past who could not be trusted to go free pending his trial.
Assistant State Attorney Bernie de la Rionda cited two incidents -- a 2005 case in which a police officer accused Zimmerman of battery and another incident in which a woman filed a domestic violence injunction against Zimmerman after a scuffle.
In the 2005 case, Zimmerman was charged with battery on a law enforcement officer and obstruction of justice after tussling with an alcoholic beverage control officer. The charges were later reduced to a misdemeanor after Zimmerman agreed to enter a diversion program and take an anger management class, according to testimony in Friday's hearing.
According to a police report of the incident, which de la Rionda read in court, Zimmerman refused a law enforcement officer's orders to back off, saying, "I don't care who you are" after the officer identified himself.
After a brief scuffle, the officer arrested Zimmerman.
But Zimmerman's family said Zimmerman told them that the officer never identified himself, and he was only trying to come to the aid of a friend who he had seen being shoved against the wall by a man in plainclothes.
"He felt his friend was in danger and he was just trying to protect his friend," said Zimmerman's wife, Shelly Zimmerman.
In the other case, de la Rionda said a woman filed papers in which she said Zimmerman smacked her in the mouth and "asked her how it felt," as well as grabbed her and threw her on a bed.
Shelly Zimmerman said her understanding was that Zimmerman was only acting to protect himself after the woman scratched him and drew blood.
"Absolutely he is not a violent person nor a threat to the community," she said.
Zimmerman also took the stand, an unusual move in a bond hearing and a risky decision for any defendant in any criminal case, much less a one involving a murder charge, said his attorney Mark O'Mara.
It was his first public statement since the shooting.
"I wanted to say I am sorry for the loss of your son," Zimmerman told Martin's parents Friday in what his attorney said was a risky and heartfelt apology from the witness stand. "I did not know how old he was. I thought he was a little bit younger than I was and I did not know if he was armed or not."