Heard died Tuesday at Saint Barnabas Medical Center, The Sunday Star-Ledger of Newark reported.
Heard's writing career started in New Jersey State Prison in Trenton while serving seven years for armed robbery. He started reading soft-core pornographic novels passed to him by a cellmate, said H. Bruce Franklin, a professor at Rutgers University, where Heard later taught creative writing.
Heard, who dropped out of high school after the 10th grade, believed he could do a better job and started writing about his old neighborhood. His mother showed the manuscript to his lawyer, who got the novel published.
His 1968 debut, "Howard Street," sold more than 1 million copies and was acclaimed for its gritty realism and insight into the urban black experience.
Heard "was a leading force in fiction because he showed how writers could take a real experience and transform it into a useful vision," said poet Amiri Baraka, a friend.
Heard's daughter said he used to list "New Jersey State Prison" under the education section of his resume.
"He wore his prison time as a badge because while he was in prison that's where he grew up, and that's where he became a man," Natalie Heard said.
Heard also wrote "A Cold Fire Burning, "House of Slammers," "To Reach a Dream" and "When Shadows Fall."
He also taught creative writing at Fresno State University, where he won a teaching award in 1970, and appeared in several films, including the 1973 movie "Gordon's War."