Davis' body was found on Saturday by his grandson and paramedics at the Shore Club hotel in Miami Beach, Florida, where the actor had been shooting the film Retirement, according to police and his office in Los Angeles.
"According to the grandson, he was suffering from heart disease," said police spokesman Bobby Hernandez. "The grandson knocked on the door, and when Mr Davis didn't respond, he called fire rescue."
Broadway theatres dimmed their lights for one minute on Friday night in tribute to Davis.
A long-time civil rights activist, Davis spoke at the funerals of Martin Luther King Jr and Malcolm X and gave voice to the famous United Negro College Fund slogan: "A mind is a terrible thing to waste."
He and his wife of more than 50 years, actress and frequent collaborator Ruby Dee, received Kennedy Center Honors in 2004 for their work.
"In the roles he took, he was a standard-bearer for dignity and integrity"
Madeleine Moore, friend and advertising executive
In the late 1990s, they co-wrote the book With Ossie and Ruby: In This Life Together, chronicling their struggles against racial injustice as well as their decades as a couple.
They also spoke in the book about their decision to have an open marriage. The couple had three children.
'Sense of purpose'
Davis broke barriers for black performers on television, stage and in the movies and developed a reputation as one of the United States' most recognisable character actors.
"In the roles he took, he was a standard-bearer for dignity and integrity," said long-time friend Madeleine Moore, an advertising executive who met Davis and his wife while working on a public affairs radio show the couple hosted together.
"Even as a young actor, he took on the mantle of this wise sage, this person who carried wisdom and a sense of purpose and the history of a people," Moore said.
Davis (L) with fellow actor Sidney
Poitier in 2002
A fellow activist, the Reverend Jacques DeGraff, said Davis' greatest role was that of an off-screen champion of the downtrodden.
"Wherever the cause of justice was in question, Ossie Davis in some way or fashion was there, lending his voice and his visibility to that moment," DeGraff said. "His loss is a loss to African Americans and really to all Americans."
After serving in the army during the second world war, Davis made his Broadway debut in 1946 in the title role of Jeb, which also marked his first joint appearance with Dee. The couple toured together in a production of Anna Lucasta and married in 1948.
Writer and star
He later succeeded Sidney Poitier on Broadway in the lead role of A Raisin in the Sun and wrote and starred in the Broadway hit Purlie Victorious, a satire of racism in the Old South. He later adapted the show for big screen as Gone Are the Days and wrote the script for Purlie, the 1970 Broadway musical version.
He made his film acting debut with Poitier in the racially charged 1950 drama No Way Out and first appeared on TV the following year in a production of Green Pastures.
Since then his screen acting credits have included the Spike Lee films Jungle Fever and Do the Right Thing, and TV projects such as the mini-series Roots: The Next Generation and the sitcom Evening Shade. He also played Martin Luther King Sr in the TV biographical drama King.
In the film Retirement, Davis, Peter Falk, George Segal and Rip Torn were starring as four grumpy old men who leave their Florida retirement homes on a road trip to Las Vegas to stop one of their daughters from marrying the wrong man.