The 25-year-old died in police custody 15 days ago after he was arrested on a weapons charge. His death from a severe spinal chord injury sparked widespread outrage toward the Baltimore Police Department.
Gray's death in custody is the latest in a string of high profile deaths involving African-Americans and law enforcement.
Many have demanded answers about what happened to Gray and his funeral drew civil rights leaders, politicians, and relatives of others who died in police custody.
Democratic Congressman Elijah Cummings of Maryland spoke at the funeral: "To mother Gloria and to the entire family, I want you to know we stand with you during this difficult time."
Cummings said he "looked at the cameras" and reflected on the great amount of attention Gray was receiving in death: "Did anybody recognize Freddie Gray when he was alive?" he asked.
Cummings said that Gray joined the church in 2001. He was in youth choir and was a junior usher.
"He loved church," Cummings said.
Gray also played football. "Did you see him?" the representative asked.
"There are those who will tell you don't cry. I'm not going to say that," Cummings said.
Gray also had a history of run-ins with the law. According to court documents CNN obtained, there were more than 20 criminal court cases in Maryland against Gray, and five of those cases were still active at the time of his death. The cases involve mostly drug-related charges, but there are charges from March for second-degree assault and destruction of property. Gray was due in court on a possession charge on April 24.
He had been in and out of prison since 2009 for various drug cases, according to the Maryland Department of Corrections.
Families United for Justice was also at the funeral. The group includes relatives of Eric Garner
, who died last July after a New York City police officer put him in a chokehold. Protests erupted after a grand jury declined to indict that officer.
Other members of the group include relatives of Amadou Diallo
, who was fatally shot by New York police officers, and Alberta Spruill
, who died of a heart attack after police threw a stun grenade into her apartment during a botched raid.
The White House sent Cabinet Secretary Broderick Johnson, chair of the Obama administration's My Brother's Keeper Task Force
; Heather Foster, an adviser in the White House Office of Public Engagement; and Elias Alcantara from the Office of Intergovernmental Affairs.
Exactly what happened to Gray remains a mystery. His family said his voice box was crushed and his neck snapped before he slipped into a coma and died.
News of Gray's smashed upper spine and the delay in getting him medical care
has triggered outrage across the country.
Peaceful protests marred
Hundreds of protesters peacefully rallied on the streets of Baltimore on Saturday against the alleged police role in Gray's death. A small group turned violent.
About a dozen young men smashed police vehicles with garbage cans, climbed on top of the cars and stomped on them.
Some hurled water bottles and other objects at police.
Others funneled their anger toward local businesses, looting or damaging a 7-Eleven, a Michael Kors store and a Subway restaurant.
Baltimore police arrested 35 people, including four juveniles. Six officers suffered minor injuries during the chaos, which ended a week of civil and peaceful protests.
Gray's twin sister deplored the violence.
"My family wants to say, 'Can y'all please, please stop the violence,' " Fredericka Gray said Saturday night. "Freddie Gray would not want this."
Journalists detained by police
Baltimore City Paper said its photo editor, J.M. Giordano, was tackled and beaten by police while covering the protests.
The paper said Giordano was standing near protesters when someone threw a rock at police. Officers responded, and Giordano was unable to get out of the way.
"They just swarmed over me," he said. "I got hit. My head hit the ground. They were hitting me, then someone pulled me out."
The incident was caught on video, which Baltimore City Paper posted online
And Reuters photographer Sait Serkan Gurbuz said Baltimore police detained him Saturday night.
Officers called the detention of the two journalists inadvertent.
"One journalist (Gurbuz) was released with a criminal citation, which is being recalled," police said in a statement. "One journalist (Giordano) was released without any charges."
Cell phone video of Gray's arrest shows him screaming and being dragged, with some witnesses saying he looked like his leg was injured.
Baltimore Police Commissioner Anthony Batts said he was appalled that Gray did not receive proper care immediately. He also said officers should have given Gray timely medical care "multiple times" -- such as at the site of the arrest and at other times during his transport to the police station.
Batts also said there are no excuses for the fact that Gray was not buckled into the transport van.
But Baltimore's Fraternal Order of Police Lodge 3 shot back: "These comments appear to be politically driven and in direct contrast to the commissioner's own request not to jump to any conclusions until the entire investigation is complete," union President Gene Ryan said in a written statement.
Five of the six officers involved in the arrest have provided statements to investigators, Batts said. The sixth officer has invoked his right to refuse to answer questions.
And while the preliminary work on Gray's autopsy has been completed, the medical examiner's office is waiting on toxicology results and might ask spinal experts to look at the case, authorities said. A full report could take 30 to 45 days.